Sounds like a belly problem..not a pack problem..As I bend forward, the weight of the stuff in the rear of the pack puts resistance on the waist against the belt area, does not allow the pack to raise up when bending. The thick front portion digs into the belly.
The leki poles are good..but if they have the extended horizontal "cane" handle..I whacked mine off..worthless for hiking and puts more torque on wrists than necessary when you really need them.I just left the loop area for tent ties,a thumb hole,and have several ways now to hold them..other than the one tortuous way they expected you to use it..
If you decide to make the modification..and don't like it..Don't blame me.It does work better for me for tent use and trail use..some people might prefer the other style of handle than vertical depending on their use..The only way I felt safe with the extension is to hold them in reverse with the handle sticking out.. ..This way I can put my hand over the top,thumb through the hole,grab around the thing in a normal ski pole grip,etc..The small hole the strap was in I use for cross pieces between two poles for the front of tents..fits fiberglass or easton aluminum poles well.I can carry the entire front 'A' of a 2-person tent by using just a small 12-18" section of tent pole,using the two lekis for the rest.
The turkey backpack..seems like a waste of strapping and space.I'd modify it with an added extra bag for lighter bulky stuff that won't fit down below..extra clothes,super light bag, and other stuff that is too bulky to carry otherwise that might be more comfort/warmth left behind otherwise.I can think of 1-2lbs of items that add a LOT to the comfort of the trip,including seat pads,foam pads,the tarp,poncho,space blanket,and a box of donuts to eat with your coffee while fishing... That could all go into an upper "bag" without you noticing the difference.
Did that turkey thing list the weight?It might weigh a lot more than a homemade pack that would hold more...
I am basing what I'm writing on my structure/weight,etc..others more than likely will need something totally different than me..just some things to consider though.