But that's what was bothering me about your solution: you went the wrong way. Because - using Navsource's jumbo-ized length of 644' for Navasota (AO-106, and Mispillion's next-sister) - by length the Revell tanker is 1/484.51 - without any chopping at all! That's already a dead-ringer for your 480-scale Revell Helena CA and Boston CAG, and only 3.2% oversized next to your 500-scale Monogram Chicago CAG, Renwal Galveston CLG, Farragut DLG and/or Revell Long Beach CGN. That could make for one helluva classic refeulling diorama - and a lot smaller than doing anything in 350-scale!
For the jumbo-ized Navasota - as, presumably also for Mispillion - the kit beam is 13.05% overscale, and so would have to be reduced by 0.24". This is emminently do-able (particularly compared to adding a whopping 5" in length) and especially if you will end up waterlining anyway.
Because of my interest and large stash of the above 500-ish scale cruisers, I wouldn't mind photographing the 480-scale jumbo-ized correction, step-by-step, on one of my Revell Mission Cap hulls, if you (or anybody) would like to see it. Just let me know (any of you, out there).
I had never heard of the tanker "jumbo-ization" refits before you mentioned it, Don. It opens up a whole new world of possibilities for these Revell flat-bottomed tankers - between 1/350 and 1/480 - you can have your cake and eat it, too!