Dektol (effectively commercial D-72) was sold as a "universal" developer until at least the early 1970s -- I've developed Verichrome Pan 620 in it at least a couple times, with what I then (around 1972) considered good results; it should be perfectly fine in larger formats, where the grain isn't a big deal.
It's probably misleading to directly compare capacity against D-76, however, because D-72/Dektol is so fast working in paper strength. Diluted 1:2, Dektol will fully develop a print in about two minutes, and will do the same for film in a similar period -- which is rather on the short side for getting consistent results from one batch to the next. I vaguely recall using Dektol at 1:9, which for paper will give dev times around ten minutes -- and in that dilution, it has enough capacity to develop 120/620 in a plastic tank without requiring extra liquid, though I don't recall if it would work for 35 mm in stainless without requiring use of a two-reel tank and empty reel spacer. D-76 1:9 would require at least 1 liter of working solution for a roll of film, however, to have the 100 ml of stock solution recommended per roll, so it's reasonable to suppose that D-72/Dektol has about twice the capacity as a similar amount of D-76, measured on a stock-for-stock basis.
From a chemical standpoint, the D-72 has only 50% more metol, but more than twice as much hydroquinone compared to D-76 -- and the hydroquinone (according to Anchell & Troop) regenerates the metol as well as acting as a developing agent on its own. To my eye, this would also tend to support the idea that a given volume of D-72 stock should develop about twice as much film as the same quantity of D-76 stock, and should be used at 2-3 times the dilution in order to obtain normal contrast in a comfortable process time. The results you get from Dektol 1:9 compared to, say, D-76 1:1 are likely to be larger grain, higher acutance, and some reduction in tonality -- but it's certainly worth experimenting with, especially in large format.
