As others note, the question is why bike packing if what works works. The only time bike packing gear ie. seat post, frame, HB bags, really pays off in a practical sense is when the terrain dictates. A rough path, traveled at speed, will either snag, rip or shake traditional gear off. Until you hit that point it's just a matter of choice.
My point being, without sounding too pessimistic, is that if you want to give full on bike packing, as portrayed in modern social media, a try you have to accept you can't take a lot of luxury items along for the ride. It just isn't made for that. If you want the extras, which is fine, you will probably be more happy with a modified set up that uses some bike packing gear and some traditional. I think that's what most posters so far have illustrated.
For example, I have always been a bit jaded towards seat post bags as being sub par. Either they are too small to hold a practical amount, or so large that they extent way back and sway from side to side. They also put a lot of stress on carbon posts and aren't really made for dropper posts. That's just my opinion of course YMMV. I resolved that by using a rack and smaller front panniers on the rear. But I also know that on a really rough trip panniers would probably shake loose or crack mounts or the impact would bust the rack bolts so in that case I would have to consider packing less/lighter to accommodate. In that case I choose a saddle bag as being a little more stable than a seat post bag.
Last edited by Happy Feet; 12-03-19 at 10:51 AM.