I am not sure what you mean by Naish 1st Gen foils vs the latest. But I have experience with 2019 and 2020 Naish foils.

I am 86 Kg and 184 cm. This spring, I started my wing foiling learning on a 2019 Naish XL 1572 cm front foil with a 55 cm mast and a 7'6" Naish 135L board. I have zero sailing or foiling experience. At first, I was not trying to get up on the foil and focused on learning to use the wing but when I started to try to get up the foil, I seriously struggled. I  was self-teaching myself and never got experience behind a boat. I debated about mast length, front wing foil size, and of course, my coordination balance. I then bought a used 2020 Naish Jet 1650 Complete foil and a used 2000 cm front wing on Craiglist's the same weekend.  I have never tried using the 1650 front wing because the 2000 cm front wing was the ticket. I truly started to foil successfully with the 2000 cm front wing, and it's been fantastic. I  sold the 2019 Naish XL because it's very similar to the 1650 foil wing.

I am now wing foiling on a 5'10" 110L Naish S25 board. I recently bought the 1800 HA but, after two sessions, went back to using the 2000 cm front wing. I did get up on the 1800 HA, but I find the 2000 cm front wing more stable, and I had just recently bought the new board. I need more experience before going down to 1800 HA. I yet to try my 1650.

I think a 2000 cm front wing foil would be best or at 97Kg; you may want to get the 2450 cm front wing first. 

I prefer using an 85 cm mast but switch to my 65 or 75 masts depending on the tide level. Hitting sandbars is worse than breaching. I did most of my learning to foil on a 65 cm mast.  My brain had fully developed the "don't breach" alarm bell before moving to the 85 cm. I still breach at times on the 85 cm, but I am fully aware and prepared. In the first session, I found the 85 cm mast more unstable than the 65 but now don't notice any stability difference when I switch mast lengths.   

You can still get 2020 Naish foils new at lower prices. While I am sure 2021 is better, I would save the money and buy 2020.

hope this helps,

Glen