Atlas has so many models I am having a hard time deciding which non-panning model is right for me. I shoot exclusively in the prone position from 1,500 - 2,000 yards. I have a couple .338 Lapua Magnums and have been using the Accu-Tac HD-50 bipod for a couple years now. The Accu-Tac bipod has no flex and I find it hard to load the bipod. I am going to get the Area 419 ArcaLock Clamp to go on the Atlas. Which model do you recommend?