180 DX Stingray! Preferably white so you can roll at night. I tried using a Champ sidewinder, but the Champ plastic doesn't stick to the ground on first contact as well as DX. Initial contact is extremely important as any slippage results in a sharp left turn and eventual 'halibut hook' shape roll.
I was playing a doubles tourney at UC Irvine 17 years ago and got the only birdie of the tourney on a certain hole with a HUGE roller. My partner CVK hit a fifteen foot putt for the bird. I should mention the roller ace on the same hole an hour later. I don't want mention the ace'rs name but his initials are Dave Dunipace. Can you guess what disc we both used?
I also roll a Pro Katana for even huger s turn rollers. The first Katana roll was completely accidental but five feet from hole #9 deeeep at Morley.