Don't worry about bulk, the knife is wide enough on it's own. The sheath+knife does fit on a shoulder-strap (there are sufficient holes to tie the sheath securely anywhere), and the retention strap on mine is excellent (quite taut), but the leather will stretch and the snap-metal will wear down over time, reducing retention - it'd be better to have a well-made snap-in kydex sheath (and/or a handle cover-flap), and there are plenty of benders here who could make or give you ideas how to improve one....
But, regardless of retention, I'd strongly discourage you from carrying it like that, esp. on your shoulder strap, or even on your pack at all. WHY would you carry your knife there?? It's not in reach if you aren't wearing the pack, it's more easily lost, and (in my opion) it's less convenient to deploy for use (even when wearing the pack) and also to re-sheath. On top of that, it's on immediate display for anyone/everyone you might meet such that they can more easily take it from you or be offended by it - popular notion: large knives mounted at eye-level are seen as weapons, whereas knives mounted below eye-level are seen as tools or more commonly are not noticed at all.
That's just my $0.02 - yes it will work, but not as well as kydex, but you really shouldn't mount your knife there anyway. The leather is 'prettier' - more suited to BRKT knives in general - and can be easily worn from the belt or drop-leg fashion (my personal preference).