Tonearm upgrade help...mmf 2.1 info

Hi! I own a Project Defut the same as an MMF-1, which means if i got it right that, its also similar to the MMF-2.1 except from the tonearm...Well i want to change the tonearm of my Project but i have some questions....The effective length of the Project tonearm is 8,6 inc (218,5mm) and its distance from the pivot is 200mm...i also assume that because Project uses the Linn mounting standard to its other TTs is the same for the Debut also (arm hole of about 3cm and two other smaller holes of about 1cm on each side...a linn template i downloaded shows another hole on top of the arm hole that my TT doesnt have..would that accept a linn arm?)...Ok the real question is i would like to fit a Linn Basik plus arm or the one that the MMF2.1 has if i can find it....but then again can i do that without drilling any holes???i dont have any relevant equipment so i want ot avoid that... So here are my two major questions:

1. If the mmf2.1 has the same plinth but a bigger arm it means that it has the arm base drilled further...but then again why did they do that?doesnt that cost more..?or is the arm 8.6 like its equivalent the Project 1.2 ?(which again has the same plinth as the Debut but has a better arm of 8.6'' not 9'' as i have read that the mmf2.1 has)..could someone that ones an mmf2.1 clarify that for me..?
Does anybody now if i can buy the arms of those models?

2.Alternatively i would like to fit a Linn basik plus arm , but then again my arm base to pivot length would need to be 1,2cm further
(the Linn is 229mm overhang 18mm, and mine is 218.5 overhang 18.5)...so i was thinking is the Linn headshell cartridge mount long enough to move the cartridge as back as i can in order to make up for that 1,2cm (or is an arms effective length measured by the minimum distance of the cartridge in the headshell?)

I am a uni student and my budget is really low so i will eagerly wait for your response/proposals...i am new in the tonearm uprgrade thing but long and loyal vinyl friend...Thanks a lot