Saving Old Seagulls

I’m aware that this question has been answered before but can’t find the reference. I have also rebuilt two 40+ engines before but can’t remember what I did. I have stripped down a Silver Century, cleaned it off and ordered gaskets etc from John. Last time I used RTV sealant on the cylinder head, base and crankcase but I can’t remember whether I used it on one or both sides of the gaskets! Apologies in advance but can anybody help with an explanation of what to do and why?

Iv'e always used Wellseal - basically an old fashioned resin non hardening jointing. You can get it still ( search Cromwell tools online etc )
Never had a problem with it ( I'm pretty sure its just rosin dissolved in alchohol ? )

Do not like silcones for anything. Horrible to clean off - goes off once opened - etc - always gone hard when you need it ( unlike other things ! )

I use this

https://www.halfords.com/tools/garage-e ... oYQAvD_BwE

works perfectly