"You can guess if you like; I'll stick with the scientific method:"
Gosh, that was ever so scientific ...
It remains true that 100 ft of film occupies just under 30 cu in, and fills (for most of us) around 18 36x cartridges. Of those, you can store 16 cartridges in about 34 cu in (w/o canisters) or in about 72 cu in (each inside a canister).
Hey, do whatever works for you, and enjoy it. Personally, I can't see space-saving as a large enough virtue to justify bulk-loading --- not given the downs of bulk-loading. The main virtues would seem to be a) it might be a lot cheaper per roll, and b) you can make rolls of 20x or 12x or whatever strikes your fancy. But (a) need not hold --- witness Arista Premium --- and (b) doesn't help on the space-saving front.
Finally, as has been pointed out repeatedly (in earlier threads), if you really need to store large quantities of film, it might be smart to pick up one of those little dorm-sized refrigerators. You can get them for a song at garage sales and such, and the cost of operating one is piddling compared to other photo expenses.
"Did anyone mention that Freestyle is selling house labeled Tri-X in 36 exp. rolls for $2.00? At that price, "rolling your own" doesn't seem economical. If you must load from a roll, Freestyle also sells their private label Tri-X in 100' rolls for about $30. I did the math and you're only saving about $0.25 per roll. YMMV."
Several times, at least in an earlier thread about Arista Premium itself. But the point is still entirely sound.