if i remember my mkII's, there is a metal retainer to slide off the cable end, a small screwdriver might be the go.
My jets are 1.8 too, they may need to goto upto 2mm tho - i can feel it, my big ported head and FR33 cam lobes can handle a bit of a fuel load methinks :)
Putting the carbs on has made me want to drive the car again - motivating me to splash some well deserved paint on the old 300,000km+ body, sadly my car has been in many hands and seen abuse from all angles (character building), i'm not innocent either but i have kept it alive this far and don't plan on giving up any time soon. The best part of the body is that it has a solid floor and hardly any rust - rare these days to have an original floor unwelded, it must have seen years of garage time in it's early life as a 1300, it also has pop out quarter windows, another rarity.
September 75 is pretty much the end of production for mk1's, i've not seen another 75' mk1 yet.