020 Gearbox - Pinion shafts... wanted wise owl !!

So i took the plunge and split my 7G code MFA 020 box, as i am going to the trouble of total refurb on everything i thought i may as well follow suit.

Bought a refurb kit from maintrans on fleabay, no worries… BUT!

As the case on my 7G box was a little sketchy in places i picked up a FJ code (1.6) MFA gearbox for the princely sum of 99p for spares…

So, i find the 7G has the old method of attaching the 5th gear (crimped tube around the selector shaft) versus the FJ has the removeable plate. Naturally i want to adapt the 7G box to take the FJ's removeable plate selector shaft - looks the same hopefully…

My problem is though that the pinion shaft on the FJ is longer than the one from the 7G, and i'm unsure if the FJ selector fork mech needs the matching pinion shaft…

And secondly - is the fifth gear cover the same? it looks it but i am cautious about the longer pinion shaft..

Lastly - to the fiddlers out there… mildly tuned 1.8 DX on 4-2-1 with a reasonabley warm cam - would you opt for the 1.6 "tighter" ratios against the 1.8's longer but faster top end?

Arn't Haynes manuals great………………….(':?')
Confused

Anyone tried this?