Put cable ties on the plug leads, 1 tie for number 1, 2 for two etc. Can be made very smart and saves a lot of bother!
Not sure if the Laverda is, but the Ford Kent is very oversquare. If you need to check the TDC mark, the old fashioned method of feeling a piston through a plug hole with a pencil won't work as the piston appears to float at TDC.
But, find a nut that fits the pencil and check for something like 20 degrees before TDC - mark the pulley and then go for the same after TDC and all you have to do is bisect the marks.
Of course you could press a dial gauge into service but us Mog folk delight in doing things with everyday objects and proving you don't need fancy kit if you understand the whys and wherefores.
The only technical thing needed to time a magneto ignition three wheeler is a dress makers measuring tape - I kid you not!