Bringing this thread back again rather than starting a new one. I read through most of the posts and think I know what my problem is, but want to confirm. To make a short story long, I ordered a Bikini frame way back last Dec. or Jan. when they first came out…talked to Aron on the phone and decided I needed flat back even though I can get my hand between my back and the wall when I do the test. I have no ass, but my wife & a number of my friends say I am an ass sometimes. Anyway, I got the frame and just had a chance to try it briefly before my hunting plans for the fall changed and I decided to sell it…mistake #1. So, I ended up just finding an older EMR frame that I used for carrying tree stands, daypacks, etc. for my whitetail hunting this fall. It fits great with standard composite stays…I can haul a stand and gear (about 40#) no problem for a mile or two without any issues. It's more than I need for what I do, but I like it so I'll probably keep it. Anyway, I found someone in the classifieds that had a slightly used Bikini with standard stays and I bought it because I really liked it when I had my original one and didn't think I needed the Duplex frame for a majority of my needs which are mainly as a day-pack. Anyway, my 4800 came the other day and I didn't have anything to do this morning so I loaded it up with about enough gear for a 3-day bivy hunt and walked around the house for a half hour or so…up and down the stairs, paced around the basement, etc. I'm not going outside because the air temperature is -12 and windchill is almost -40. I had about 35# in it including my bow strapped to the back. I had a majority of the weight on my hips and felt very little on my shoulders…good lift and lifter angle. What I did notice is that I had quite a bit of pressure on the lumbar pad. Not a big deal wandering around the house, but I can see that it could be a potential problem if I'm hiking four or five miles and even more of a problem if I put 50# or so in it. I have no illusions that I'm ever going to be carrying 80-100# as I'm 47 years old with a screwed up back and a hip that's starting to give me problems, but I want to make sure I can haul 50# give or take comfortably. Am I wrong or do I need to find a Bikini frame that has flat-back stays? I suppose I could order one and then decide which fits better, but want to be somewhat sure before I drop money on another new frame. Thanks.