I would say forward as it will make your two anchor points (rests) further apart and should be a more stable platform.
Also watch and see if it shoots differently, I’ve seen heavy recoiling rifles have the muzzle flex down when fired with bipod legs at an angle like this. Please post what rifle and cartridge/load you are shooting plus results results. Also if you don’t mind, if it has a brake and what brake it is (especially if top ported).