As much as it pains me, in your case I'd go with the .284. Here's Why:
I love my Patriot, it was my first "custom" rifle & will always be near & dear to my heart. Why I would not choose it quite frankly, is the 168 Berger.... I just don't get it. A light, highly frangibly bullet @ high velocity (although a good bit slower than it should be) is a recipe for some bad ju-ju (IMHO).
RL-22 has shown pressure issues with my testing in a 243ackley, so you're right on there. What temp did you work up the load in & will it be similar to the temp you're hunting in? I would not be afraid of 15-20fps difference.
Just as a discussion piece, I've been shooting the 168TTSX in my Patriot with RL-17... Velocity is, as of my last test, just north of 3400fps, a solid 200fps over your RL-22 combo. With 3 loads on the cases to boot.
I don't trust the 168Berger on a big muley. Will it work? Probably. Not that same Patriot case with the 190 or 210 Berger is a whole 'nother story. (I have a couple hundred 190's to test- Don't tell Broz
The 284 is slinging a high BC & just as important, high SD bullet at really good velocity.
Either will probably kill just fine. For this situation, as much as it pains me to say...
I vote for the .284.