what exactly type of Helios did you use? (44M, 44-2 etc.) I have most of them and can try to replicate your problem. If I succeed, I can make few pictures to suggest the solution, if not, we’ll at least know which types are not suitable for the mod.
I can make the mod for you, and it will cost 99 USD with the lens in fully working order (+ shipping) but I am sure you can pass much cheaper with DIY.