The whole concept of towing with a tractor beam is somewhat hazily portrayed in Trek. Does the tug need strong engines, or does a strong tractor beam somehow do the trick of moving the load? We have seen Wesley lifting a supposedly not insignificantly lightweight piece of furniture with a handheld tractor beam device in "The Naked Now"; the amount of physical effort evident is in no way comparable to what would happen if Wes tried to lift that chair with a rigid pole of equal length!
The handheld device jibes well with a simple runabout being capable of moving a Galor
in "Emissary", as well as a few other feats including the E-D moving an entire moon...
Both the "11001001" pod and the "Favor the Bold" spacecraft could be relatively humble affairs, only the former concentrates on having agile manipulators while the latter has robust ones plus a whopper of a tractor beam... The rounded "shuttle" introduced in ST3 could in turn be a pure tractor beam type, with the (apparently intended?) ability to move big starships around. A spectrum of types, rather than wholly different categories, perhaps.