IN ALL CASES the gasket must be in place on the "roof" of the cover: measure from that.

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Setting the droop, how much it droops to 25mm is relatively easy, just remember that to adjust it one has to adjust (bend) the little tang/tab that stands vertcally behind the needle & seat. I used one side of a pair of pliers to push it in a bit as my droop was 30mm instead of 25.

That's the easy one.

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The 15mm "gap" is the one that stops the fuel flow so too wide and fuel starvation (flow is stopped early) and too narrow and fuel flooding (too much fuel allowed in). There is an arguably more accurate way to do this (the 27mm depth method) , but I am sticking with the 25mm/15mm accepted standard for now.

So I have struggled and struggled to understand exactly where the float should be when measuring the 15mm. Finally I found some words in Des Hammill's book (page 43) that I think have at last helped me to get it right. He says as follows: 

"If the top is slowly tilted back the needle will move in towrds the seat, and when it stops moving, THIS is the point at which the distance betwene the float and the gasket must be measured."

That sentence is why I have made this entry. There are many many examples on the internet and probably youtube. Watch/read those and then this sentence when it will finally make sense where to measure the 15mm. Any old ruler will do, no need for micrometer stuff.

I dread to think how the car survived our ten day holiday with the floats like they were - it explains the massive flat spot at about 6,000, because it was running out of fuel because the float was cutting it off, 20mm instead of 15mm.

Here's the extract from page 43/44  Des Hammill on page 111 of his Carbs book ISBN:978-1-903706-75-6