hmmm weird science here
I think you are messing with fire err ice- so to speak.
you're ignoring the basic reason why you are eating CVs, it's the angle I presume...I'm no expert on these things mechanical but I read everything I can lay my hands on. People a lot smarter than you or I have tried most of this stuff repeatedly.
add me to the list of trying to talk you out of going to 15s especially on a rig as lifted as yours is said to be... It's a generally accepted fact that 3" lift up front is the limits of reliability. Have people done more-sure they have. Does it get expensive-why yes it does. You allude to that already.
Would love to see a photo link to a view of your CV angles. You read the Sonoran Steel website FAQ section for the 3rd gen Runners? Steve S. over there has been there and done that on virtually every combo known to mankind.
You seem determined to go it your own way. The results could be disastrous but you seem to think you have it all figured out. Tread cautiously sir. I fear for your rig and your passengers. You've already relocated your brake bracket out back, you've removed or lengthened your panhard bar? You're messing with some dynamics of physics I am not fully convinced you have all thought out.
None the less I remain intrigued....and will follow along. What tires are you loving so much that you can't get them in a 16? Better yet step up to a 17 and go even bigger on your brakes like the 231 caliper Tundra setup mentioned by Liny.
Sorry to be such a Dad.:rant: