I know zilch about these boxes, but there may be some alternate internal choices (mix-n-match) that improve the recovery.
I'd like to see less than 20% loss going into final gear (which may not be OD), even more if the engine is flat at mid range.
Before you pass/fail on a specific gear set:
1. the start ratio (1st, whatever) should work at your push speed, or whatever your clutch will take
2. intermediate ratios that shift below 100 mph relatively unimportant
3. if you have a dyno plot, look at how far down you have good power - that's got to be the recovery point going into 4th and high, even if you must over-speed it a bit (i.e., safe, but no power advantage).
E.g.: Low power below 4,300, max RPM for shift 5,500: needs 78.2% recovery (.78 OD, or 1.28:1 4th gear)