Kit contains a diagram for needle and float height. Needle "shoulder" and little washer should be flush with the deck of the piston body for starters, IIRC.
You can "cheat" the adjuster tool need by pinning the piston thru the intake hole with a finger (so as to not put twist on the diaphragm) and use a long 3mm Allen wrench to adjust the needle. Word of caution: it doesn't take much to change the mix... 1/8 turn makes a big difference. Clockwise (viewed from the top) raises the needle, anti-clockwise leans. It'll get much clearer after you've been through one. They're very like an SU.
_________________________
'64 MGB
'67 Lotus Elan S-3 DHC
'69 Lotus Elan +2
'78 Alfa Romeo Spider-current Daily: O=\*/=O
'84 300D Turbo:"Diesela"-SWMBO's Daily: OO|#|OO
'66 Alfa Romeo GT - Upscale Yard Art: Oo=\*/=oO
Hey! I LOVE my wife... She lets me drive her MG!