I am fairly new to quad skating.
Well then, welcome aboard.
I am trying to get into more of the artistic, Jam, style indoor skating.
Help me out here, Jam sk8ing and artistic sk8ing are 2 different things..and generally use 2 different types of sk8s.
I am looking to build a custom pair of skates. I urgently roll Riedel Angels 111
That is more of an artistic style of sk8, but way too big to have a plastic plate. 
size 13 which is too large I think I needed a size 12, or 12.5.
Adults need to have properly fitting boots. I get absolutely ill when I see someone on the lookout for boot x in size 9 or 10. I got news for those folks, while one can get away with a "sorta" fit on street shoes (like going up a size to get a better width fit) that does not cut it in sk8s. Even a 1/2 size off can make the difference between OK and awesome.
I plan to move up to the OG boots because they are real leather as opposed to those man-made stiff boots that won’t break in.
Let me clarify here. The boots are 172s. The "OG" designation is for the model of sk8 that Riedell uses them on. (I had to look). Nice boots BTW if you are into that kind of thing. That is more of a JB style of boot.
My question is should I go with an Arius plate $345, or one of the Roll line plates? I weigh 245 lbs, I do not plan on jumping. I may learn how to spin someday. But I need to be able to Jam Skate.
How high is up?? First off, I'm still not exactly certain what kind of sk8ing you want to do. I have seen folks jam sk8 in high tops, but the really good one use low cut speed style boots since heavy boots / sk8s really do not help folks with a lot of the jam style moves.
If I need a size 12, it doesn’t seem as if the remaining roll line for the plates that will accommodate.
Uh I have put Roll Lines on size 14s great success. (I ignore the manufacturers recommendations. They truly limit performance possibilities.)
The other question is whether not I need a 45° angle king pen pivot truck with a 22.5degree, or 10° king pen foot plate truck combination for what I plan to do.
I have seen sk8rs on everything from Labeda Pro Lines (5°) to Sure grip Avengers (30°, ignore the whole DA45 thing, that was a naming convention I fought against and lost when Sure Grip brought the DA45s out. 
)
What are the pros and cons, because the seem to be in the same price-point.
Or should I just look for the sure grip/Power dyne advantage avenger plates. I was just wanting get a plate that responds without seeming that the trucks are too loose and swirly?
Any advice helps