I have been experimenting on a different tack. Imnproving the response of the PA driver stages.
I used MPSH10's in my test board build and FT37-43 toroids wound as either trifilar or bifilar according to stage needs, of 10 turns.
Comparing the original uBITX driver which has a ~7db less gain at 10M end, this version has ~2dB drop.
I don't have any spare output FETS or I would check that out also, driven by the this test board.