RE: synthetic oil as patch lube
same here,it is not to have PETROLEUM oil in it,could be cheap way to have great patch lube.
i would guess that the lightest weights would be best,dont know if they make a straight10 w in syn.
you could take a whole strip of pillow tick and soak it and wring it out and let it dry.
i dont believe it would freeze in winter also.
then cut it at barrel.