Definitely the PB bag; much better than the inov8 (the smaller one without the bladder).

As others have said; loosen the compression straps, do up the waist, then do the compression straps up again. Once you've got the waist tension correct, you'll never need to adjust it again. Just release the compression straps to swing the bag round to the front and unzip it

Make sure the straps run below the hip bones otherwise you'll get stomach ache (true of all bumbags)

Often have to check i've still got it on, even when full; just don't know it is there!