IMHO, let the gun sit as nutral as possible. By pressing into the bipod or by pulling away from the bipod, you are using muscle to hold your position. Muscles are subject to fatigue and it is hard to replicate the same position from shot to shot.
I am wrong at least twice a day, your milage may vary.
I like to let it sit neutral as well, with the legs as close to 90degrees to the stock as possible. That way I'm not stressing/torquing anything that may cause inconsistent POI. My impact is sensitive to this.
Also because of the arc like motion of the the bipod legs, keeping them at 90 degrees means that any movement from that position due to me or whatever mild recoil there may be is almost entirely forward/back. If the legs are 45degrees forward or back then it introduces a larger up/down component. Some of my guns are sensitive to this (red wolf) and others not at all (crown). Suppose it also has something to do with the quality and rigidity of your bipod in various positions.
Gotta see what works for you as I see others with the same guns happily shooting with their bipods in all sorts of positions that don't work for me.
I get the best results when benching my guns with the bipod legs extended forward as it seems to rock less for me, at a height thats comfortable to look through the scope. As a right handed shooter I grip the gun at the trigger area (handle/grip) with my right hand and let the butt of the gun sit in the web of my left hand between thumb and pointer finger touching my right shoulder. I use my left hand to point the gun at the target then a firm squeeze with my right hand to steady the rifle, a couple breaths to relax before squeezing off the shot.
And to always set it up the same way (consistency, repeatability).
Now I often see bullpups having the bipod legs extend far forward (say 45°), not just straight up. Sonny, or anyone else, could you explain that a bit?
In the powder burner world you load the bipod. If I’m shooting my airguns with a bipod then I load it up to some degree. It make the position feel more solid to me. If I’m shooting off a rest or pack then neutral. But do whatever is repeatable for you. Consistently is the key. Paul
I shoot my AG's and 22rf's neutral and relaxed with legs mostly 90 degree unless I need the rifle lower but this is off the ground down prone. Off a bench I often have to have the bipod legs at an angle to get low enough to be comfortable. I think that comfort is one of the most important aspects of making consistent shots.
The PB's I load the bipod sightly, just to where the bipod stops it's flex, and that's for recoil control with the objective of having the rifle come back to the same place in the sight picture to see where I hit or miss at long range.