Please send for the service kit. There's no point in putting the old Float Needle Valve back in. The base-filter unit can be cleaned but they come with the kit so put the new one in. The Float Needle Valve is not the innocent little thing it looks like. The little plunger on top is part of a micro-spring loaded system with an ultra tiny spring inside it. With constant daily use they last decades but if left unused for say a couple of years the springs can become corroded and stick adding to fuel delivery problems.
As for float settings:
Using a steel ruler with a bit of masking tape wrapped at 7.5mm mark use this video but you only need to make sure
that at the furthest point from the axle the float-corner is 7.5mm +/-10% to the carb body when held close the the angle the carb will be when in-situ. Float adjustments are best done with the float off to prevent damage to the Float Needle Valve.
https://www.youtube.com/watch?v=g6y32Gw5HK4
Tip: Keep a magnet handy and stick the axle to it when stripped out 
When all done and happy the icing-on-the-cake is to balance the carbs as per,
http://straticus.epizy.com/SV650CarbBalance.html