Thank you Naz fer yer advice.
Took keyed washer ~1.5mm for variator space out with still giving good threads and ground the swingarm down to get belt alignment at full variation really close to straight.
Test ride and bam, flywheel nut fell off... So put a lock washer on that side too!
Going to put the bike through some paces this weekend see how it does. Currently running pretty rich but figured that's fine for now.