I actually like the fact that they "ride high". The last thing I want (though the vast majority of the time, I carry my bag in one hand - by my side) is a bag that positions the tuba's bottom bow so as it thumps against the backs of my knees with every step I take.
What is your frame of tallness?
At 6' 4" I have to be very careful getting through doors, low branches, etc. when I backpack my Tuxedo.
Joe, I've seen that done before -- I've tried that before, and I think its pretty ridiculous.
Just pick the tuba up by the top bow, hold the bag upright, and slide it in. Not hard. BTW, one reason why I think Alteiri bags are awful is the stupid drawstring that gets caught on everything. That plus the open top/separate cap design has always been a head scratcher to me... I just don't like them.