It actually states use 0.5 (Think yours is a typo) but yes I agree much too thick.
I used 0.15 thread, much easier to tie and looks tidier bearing in mind you have to add the futtock shroud as well
The instructions are a good guide as is the build diary but go with what you think looks good on your model after all you are the one who will be looking/admiring it
Current Build:-
[color=blue]Stash Avro Lancaster (Full Kit)plus some extra issues I picked up at a good price
[color=blue]Built:- Norman Catapult by Mantua,Roman Catapult by Mantua,HMS Victory,HMS Victory XSection,Focker DB1,Bismark,English Carronade Titanic Lifeboat,American Civil War Gatling,Hummer,Sopwith Camel F1,Occre Jupiter ,OcCre Wagon, Latina Arab Dhow, Eaglemass Orrery OcCre Rogers 119 [color=red][color=red]RB7,OcCre Missippi River Boat, Model Airways Fokker DR1
OcCre London L>C>C 106 Ugears Scrambler, Ugears Hexapod Explorer UGears Off-Road Vehicle