I don't use the shake method, but I thought the main problems with the shake method were that some compounds that form head only form once (i.e. the shake method will destroy head retention), and that if you do it *above* serving pressure, you can seriously overcarb the beer in a hurry.
Correct me if I'm wrong, but if you do the "shake" method at the actual target pressure, you won't run the risk of overcarbonating the beer, right? It's only doing the "shake" method at higher pressure that can cause problems?
So if you're at 73 degrees and you set your regulator to 30 psi, and shake the crap out of the keg, you won't get the beer to absorb more CO2 than it's "supposed" to at that pressure and temperature. And since that pressure and temperature is an acceptable number of volumes CO2, it should work, right?
That's correct. It can only absorb a maximum of whatever PSI you push into it. That's why the set it and forget it method ALWAYS works the same, because you're setting to 12psi and letting it reach equilibrium naturally. However, keep in mind that you're at 73 degrees, and the beer doesn't want to absorb anywhere near 30psi.
However, the shake method is done because the beer isn't naturally inclined to simply accept any pressure thrown at it. Assuming the beer is cold and you've got the PSI up a good bit, you can probably absorb 30psi over a 2 day period, and end up reaching the same pressure as doing 12psi for 2-3 weeks. It's just that you're forcing it in faster, and it needs time to really settle. This includes venting off excess pressure, waiting for the airspace to reach equilibrium with the beer in the tank, etc.
I just kegged my first beer this past Friday, and I chilled it to 41F, then shot it with 30psi and did 10-15mins of kegrolls, then let it settle for a few hours, vented it, then hooked back up to about 25psi for another day. Disconnected, let it settle for a few hrs, vented a bit, and hooked it back up at about 10psi. It poured a good bit of foam initially, but turned out fine by Sunday, and pours perfectly for me (a bit fast though, due to my shorter beer line).
You
can get this thing kegged and carb'd, although it's not going to be the same as giving it extra days from a standard force carb, and you're probably going to end up with a bit of a mess initially. That's why I recommend carbing it up now. If you can get it cold and carb'd now, it can survive the trip, and simply require a few hours to re-chill and let everything settle once again. I'm new to kegging, but that seems to be how it works for me.