Fitting a Pack With Early Onset Middle Aged Spread

Hey Folks! I was wondering if I could seek some advice on a pack purchase / fitting?
I'm fairly new to bushwalking and am in the process of gearing up for the south coast track. As part of this I'm looking at a getting a pack with the following constraints:
. 75 litre give or take
. Loads 20kg well
. Reasonably durable
. Not fussed about pack weight
. Price isn't an issue
I started trying some packs last weekend and will resume my search again on Sunday. Of the two packs I tried (the One Planet Strezleki and the Macpac Cascade 90) neither seemed quite right.
After playing around with my current pack (an Osprey Kestral 38) during a day hike yesterday, it occurs to me that my hard earned belly may be getting in the way. So currently I can clip the harness below my paunch, where i find the pack will slowly slip down, eventually placing load on my shoulders; or I can clip across my stomach as the design intends where I get a better fit, but the strain of tightening the harness becomes rather uncomfortable.
I'll be trying the above packs on again (the guy at Pinacle was not interested in adjusting the Strezleki at all and abandoned me after I told him I planned on carrying more than 11kg in my pack, so I'll be heading into Snowgum who also stock OP; and there was some more tweaking to be done with the Cascade but I ran out of time and was not going to buy until I was certain with the pack).
In the meantime I was wondering if any one has any input that would help with with this purchase? Has anyone had a similar experience in regards to body shape, or has any suggestions for a pack that would accommodate my shape (I'll spare you the pictures, but I have a pretty standard beer belly)?

I'm fairly new to bushwalking and am in the process of gearing up for the south coast track. As part of this I'm looking at a getting a pack with the following constraints:
. 75 litre give or take
. Loads 20kg well
. Reasonably durable
. Not fussed about pack weight
. Price isn't an issue
I started trying some packs last weekend and will resume my search again on Sunday. Of the two packs I tried (the One Planet Strezleki and the Macpac Cascade 90) neither seemed quite right.
After playing around with my current pack (an Osprey Kestral 38) during a day hike yesterday, it occurs to me that my hard earned belly may be getting in the way. So currently I can clip the harness below my paunch, where i find the pack will slowly slip down, eventually placing load on my shoulders; or I can clip across my stomach as the design intends where I get a better fit, but the strain of tightening the harness becomes rather uncomfortable.
I'll be trying the above packs on again (the guy at Pinacle was not interested in adjusting the Strezleki at all and abandoned me after I told him I planned on carrying more than 11kg in my pack, so I'll be heading into Snowgum who also stock OP; and there was some more tweaking to be done with the Cascade but I ran out of time and was not going to buy until I was certain with the pack).
In the meantime I was wondering if any one has any input that would help with with this purchase? Has anyone had a similar experience in regards to body shape, or has any suggestions for a pack that would accommodate my shape (I'll spare you the pictures, but I have a pretty standard beer belly)?