Axle flanges for 915-to-930 axles

I am installing 930 rear suspension pieces in my '81 SC to cope with a 964 motor swap. I retained the fine-splined 915 trans and need the correct drive flanges to mate the trans to the 930 axles. The CV's use six 10mm screws. I believe the flanges I need would be from an 80's Turbo, but they are hard to find. I have been told I can also use G50 flanges with shims. Are there other options?
Thanks in advance!