Thinned spar varnish wants to dry too quickly, which gives very little working time to properly apply without getting tacky and "grabby". The boiled linseed slows things down a lot and allows plenty of working time to level everything out and cover every little place on the stock. Cannot over-emphasize very thin coats either. The first couple need to be wiped off, leaving nothing but what has penetrated.
I agree the finish you have applied should be removed with lacquer thinner and allowed to totally dry out for a couple of days before starting over. I would stay away from tung oil in the mix.
I've tried all of these concoctions and more over the years, but I've quit that and now use Timberluxe No. 2, which is their thinner version. It's easy to apply because it doesn't become tacky too quickly, dries/cures fast, and is as durable as any of these kinds of classic, hand applied finishes can be, and it is easy to repair.
Nothing is as durable as the conversion epoxies like those on some target guns, but they just don't look right on a classic gun.
JR
