Jesus Christ of Latter Day Saints!?! LOL, brutal!!! I'd be worried bout any type or bearing bushing with such a high spring, what I know is bearing bushings are meant for use with high speed set ups, yes, but at under 330fps velocities. Also, PDI springs are so varied in past years they can't be trusted anymore. Different lengths and wire thicknesses. Examples with 150% springs, I had one that shot 350fps in my MP5, was 6 3/8" long. Have also had ones that had thicker wire and up to 7" long, that were a bitch to install and also put out upwards of 450fps. Imagine those non-existant tolerances with a 190% spring, you might end up with a lemon (75% chance) that'll shoot over 500fps.
BTW, the 16 gauge "low resistance" wiring doesn't do shit, just make sure you install Deans Ultra plugs to replace all the connectors and that'll give you a lot lower of a reistance drop than the wiring will. Stuff found in TM mechboxes is #18AWG teflon insulated wire, similar but not quite the same as mil-spec aviation grade wire. The difference between #18AWG and #16AWG is roughly 1ohm............... per 1000ft. What the #16AWG stuff you are looking to use will give you, is increased current handling ability, which you'd want in such an insane idea like the one you have.
Good luck with it all!