I know that on the Qwic Fly installing a "Newer" .61 was a bit tight as the front case is normally longer on the newer engines verses an engine like the old Super Tiger Blue Head which front case is very short. The Kraft 61 I used did not have a remote needle and I had to put recesses in the firewall for the back plate screw heads to get the spinner clearance down to 1/16". The Primus I am finishing really does not have a nose ring and therefore the spinner can be located way out front if necessary with out looking weird. I can not comment on the other designs in question.

I hope this helps a bit,

Cheers,

Marty