can Ra ever be channeled again?

[Aloysius]

Ra scanned long and hard before finding a match that could hold their vibration for any length of time.

It's not a matter of holding vibration. In fact, such a concept doesn't hold any metaphysical water. Similar mentions of purity and tuning are exclusively descriptions of L/L Research methodology.

The only factors and variables are clearing the mind, going into a proper trance and doing the job right with proper protection. And perhaps you're correct in the sense that it is relevant if the body at hand can handle it as well.

There is nothing divine here. In fact, in my assessment, these entities want as many people channeling them as possible. They want a grassroots and massive movement.

I'm sorry but I disagree with you thoroughly here.
Vibration, perhaps an ambiguous term within the context, is a factor to consider: "narrow band vibration" and all.

L/L Research are responsible for giving us the Ra Material and the Ra material was produced by the blending of Ra with three members of L/L Research so to discard the terms they use is perhaps a little too brave. If you believe the Ra material holds water, but reject the terms that Ra (and L/L) uses, then I am left befuddled lol. All things are a product of something else, if we can't see the immediate connections that does not mean that are not there, or that they are inherently devoid of value.
Also I would like to know what metaphysical "system" you are using to invalidate such proposals.
Also, grassroots? lol i dunno bout that, perhaps though...

Anyways to your point Plenum; Well yes, but not in the same way (if that wasn't obvious LOL). There's a whole bunch of people claiming to have channeled Ra (non trance style) and to be honest I have yet to see compelling material produced by these folk. I'd say it's possible but I think that it's for the most part a pretty fruitless endeavour, though don't get me wrong I would like to see it if a bunch of well trained and dedicated peeps were keen. Hell I'd even offer to go trance, but not for Ra maybe another "confederation" entity, I owe Ra enough already lol. I think Ra got their message through.