Good to see your not hanging on to the past Jas
If that MSN does need a tweak it will only be a small one. The spray bar that is on the other end of the MSN screw has 4 little holes drilled in it at 90 - 180 - 270 - 360 deg. As long as one of those holes is lined up directly with the end of the HSN assembly (so you can see the hole if you were to look down where the HSN assembly screws in) then you are on the money. At most it will be out by 45 deg. Having the adjustment screw flush with the carb body just keeps this spray bar hole close to the centre of the HSN assembly, which is it's correct position.
I am sure you guys will have loads of fun getting the new toy running sweet as a nut. After all, that's half the enjoyment of these little beauties.
If you run into any issues with parts for the Vertex, I have my original Vertex motor here (about 8 litres through it). including pull start etc. Only thing wrong with it is the pull start cord is broken, and is only about half the length it should be. Otherwise it runs strong as. I am unlikely to ever use it so if you ever need it we can work something out.
CU [8D]