Is there any need to use the standard 0.5mm washer when using adjustable needles in regards to does the washer serve any other purpose other than raising the needle? I ask as im trying out a budokan jet/needle kit ive had for a while and thinking back to when i removed the kit from a set of carbs a stock washer was used aswell.

Just as you say,The washer is only there to raise the needle.
So using the adjustable needles means you don't need washers.