I used JE Reel for my driveshafts. For the rear i did thick wall tubing and Superduty Yokes and Ujoints with custom drilled flanges. For the front i used stock fj60 yokes and ujoints and smaller diamater thickwall tubing. I have a 4l60e and fj60 front axle though so it might be slightly different. You can call JE Reel and tell them about your clearance issues and they can get you set up with a smaller yoke at the tcase flange.
The double cardan drive shaft question really depends on how you have your rear axle set up. Do you have your flange on your rear diff pointed straight at the transfer case? Or is the flat portion of it vertical and parallel to the output flange on the Tcase?
Double cardan needs the flange on the diff pointed straight up and at the t case. if thats how you have your axle set up then youll need to use that or youll get crazy vibrations.
If you have your rear axle set up like standard, you need to get it rotated to be as close to perfectly parallel with the output flange on the t case and you can run regular ujoints.
For the front axle you have less to worry about. The high pinion third on the 80 series axle actually gives you a better driveline angle than the low pinion fj60 diff.
