I use an Arca swiss Compact also, with 4-5 lenses, extra bellowws, meter, film ,etc. and struggled as you have. I opted for the larger F64 pack, which I believe is labeled the BPX. I find it sturday, well designed, easy to configure without having the added expenses of Gnass type bags. The Lowe line, especially the pack Dykinga uses, is obviously a wonderful unit. I simply found the F64 an equal alternative.
Bob