After I became aware of the original jump fuel usage rules, I dabbled around a little bit w/ using them along w/ drop tanks as indicated in some of the early TNS dispatches where the 3I was planning to upgrade the Xboat net to J6 capability.
I figured GDW must've at least kicked the idea of 'shrinking' the 3I around & there was never any definite indication that it was actually dropped. Mention of the scheme simply ceased after some disaster, as I recall.

Anyway, upgrading the xboat net to J6 definitely would've cut standard commo times altho it was later established that the IN had it's own net of J6 'couriers'. And since those vessels could  use a 'short-cut' across the Rift, 'official' commo time from Capital to Regina was already a whole lot less than the 'commercial/civilian' time.

Using the original rules (all or nothing fuel usage) along drop tanks *did* change things a lot but still made for an interesting, IMO, Travelleresque setting. Availability of drop tanks became a prime consideration.