I'm making my first MYOG pack, which is also my first foray into frameless packs. Straps and hip belt pieces are done, and I've mounted them on a mockup of the pack bag. The mockup has worked well to adjust strap angle, spacing, length, etc. and make sure the pack volume is right (30+ liters, or 28" X 12" X 6" including 8" extension collar).
Here's the problem: Using either partly inflated Prolite or CCF pad, folded or burrito-style, the virtual frame becomes somewhat convex when the pack is loaded. I find this uncomfortable (or at least, it feel weird).
If I reach back and tug the top of the pack toward my shoulders (as load-lifters would) it feels better. Should I add load-lifters and take the (minor) weight penalty? Is the rounding-out of the pack just in the nature of frameless packs? Will the pack conform to my back better after a few miles? Will compression help? (The mockup doesn't have a compression system, but the actual pack will.) Are there other virtual frame systems that work better?
I'd like this to be my go-to pack for trips up to 5 days or so, and starting pack weight will be generally 15# or less, with ~7# base. I'm trying to keep the stripped weight of the pack around 8 oz, using dark gray Xpac (vx 21?) and 1.9 oz silnylon, with minimal features. Ideally, in its lightest configuration, the pack will be part of an SUL kit I'll be trying next season.
Thanks for the input.