*how* is one to be Harvested?!

[Siren]

What will be the actual "engineering" technique used to get a soul to arrive in the upper dimensions?

Basically, the same process that would get, let's say, an ape, to arrive into this "dimension" of human-beingness. The key is: awareness.

In the case of 3D to 4D, it is my impression that the process is based on the quantum expansion of awareness of the entity in question, followed by a self-realization or crystallization of desired purpose, in the form of a kind of service. The 3D entity at a point comes to the realization that it desires/seeks/strives to serve everyone/everything for the greatest good, or serve solely the self for its own greatest good. This, fueled by will/faith in the chosen/desired path of seeking, catapults, shall we say, the entity into transitioning towards its next experiential cycle (that being the vibratory spectral field that is 4th density).

what will this Harvest-event look like to an observer standing 50 feet away?!

I don't think it will be "observable" the same way you would observe an aircraft lift off from the ground. Other than that, I cannot presently answer this question.

Someone got irked at me when I said that Death, in the usual way, is also harvesting.

One need not be currently incarnated to be harvested/graduated into the next experiential spectrum/density.

I ask this as I have read from some very well meaning Channelers that "portals will open" and one will just step through them, for those who will be Harvested.

I believe the whole "ascension-portals" idea is, quite frankly: unintentional misinformation and/or deliberate disinformation. Either way, this seems to be quite a pervasive idea among New Age circles and the such.

---"poof" into thin air! if many go all at once, why those 80 mph going cars, on the rush hour interstate, will suddenly have no drivers!

You are asking for responses to these particular queries. So my response is: it will not happen this way. The transition wont occur instantaneously nor will it be a collective phenomenon, whether localized or globalized.

---a archway portal will form next to the Chosen person and they walk in, clothes and all.
or....the clothes drop to the ground, empty!

Again, same as above.

---the harvested soul "dies" in sleep, going out of body and not ever coming back: found dead in bed, that morning, of unknown causes.

This would appear to be the most common way. But death itself is not necessarily the only means to harvest.

----the harvest timeframe is 70 years and each of us is harvested via death, in the usual way. but each of us will arrive into a NEW heaven, not the one that has been there for 1000+ years!

See above.

---there is/are disasters that will bring a huge harvest of death-ascended souls, all coming in at once.
...or a sickness epidemic.

Natural "disasters" are indeed assisting in the transition process. Death will also quickly "cleanse the fields," shall we say, by removing, or displacing, those entities that due to, let's say, blockages or limitations in awareness, are either not ready to withstand the incoming vibratory qualities of 4D and/or are not willing to adjust/align to these new vibratory patterns.

I believe sickness or epidemic, whether natural and/or man-made, will contribute to the process as well.

---alien spaceship land and take away many people.

You mean abduction? That is not harvest. Nor will the Ashtar Command come and "save" anyone. This is contradictory to the Law of Freewill.
In isolated instances, however, this could be applicable to certain groups of entities or individuals ("special cases," let's say), but I imagine this would be extremely rare and unnecessary.

Harvest, ascension or graduation has to do with the degree of awareness*, intensity of seeking, and direction of service of the entity in question.

*Capability of informing oneself with, and thus partake/enjoy, greater degrees of light/awareness/intelligence.

On a side note: perhaps it should be useful to consider that the so-called "ascension" is not exactly upwards, but rather inwards.

I have read that term "Harvest", now, for years and i *still* do not know what the writer means by this word! problem might also be that out of 100 people saying that "harvest" word, they might each have a different meaning that they give to this word!
I "hate that": where a simple word like "love" actually might have 3,831 meanings!

Ah, yes. The beauty of semantics/pragmatics!

I suggest seeing harvest/ascension/graduation in a more scientific term: a quantum leap in consciousness, if you will.

then there is the Second part of the "harvest problem"!
---is this harvest going to happen within one year or so, or be spread out for 40 to 90 years?!

I would advise you not to concern yourself with temporal calculations. Trying to "nail" a date or time-frame will greatly mislead you from your goal at hand. Future events are always being, shall we say, re-shuffled, by the present moment. Certain events are universal in nature. Such is the harvest at this particular locus, but "when" or "how" are inconsequential details in the great scheme of things.

It is my perception, however, that the harvest upon this planetary sphere will be largely (if not entirely) an individual event that will/is occur/ring over the span of a few years, rather than a collective phenomenon happening in the blink of an eye.

I have been reading, of late, about "strange deaths", in the paper or on the internet. one case in point, here in the local paper, Tallahassee. On a golf club golf course, a player hit his ball from the starting tee. a long long drive. along the green is a row of expensive homes. the ball was hit and it went over the green boundary line into the area of the homes and there was a lady lying next to her pool, sunbathing.
the ball hit her on her head and killed her instantly!!

And that was by no means a coincidence, I would add!