My Reax Pearl layout is 70 x 3 3/8 x 30 with a double thumb balance hole. 1 3/4 from the edge of the thumb assembly. Pitched 1 1/4 away from the thumb.
this layout works great for me. i have try it on a house shot. and love it.
i also try it on a 47 foot pattern. for this pattern i had to put a little surface on it. i took it down to 2000 grit. once i did that. it had more backend movement than the solid Reax.  thanks Radical for making this ball.