Having just re-finished my main and z masts , I thought a few may be interested in another data point for Bristol Finish. I had considered a few products, but decided on the bristol product for various reasons. Others on this list had mixed reactions to the product so I figured I'd add in my experience. Generally I am not at all certain I would use it again, it depends on how well it holds up.
Firstly, it runs about $60 per quart, and a quart it took to get 4 good solid coats onto my 35 ft spruce main. The Z took about half that. I had to wood one entire mast surface (the nominally south facing surface), but otherwise I was putting it on over a good existing coat of something. I do not know how or when these masts were previously refinished, but it looked like varnish as it curled out of my scrapper.
I had refinished a short portion of the main that I could reach from the deck last year with cetol, just to see how it would hold up. A year later it looked ok, but you could remove it with but an easy swipe with sandpaper. I'm not sure how that relates to weathering, but it certainly was not a hard durable finish.
I did 4 coats over a two day period when the weather was in the 50's by day, 30's at night. I recoated after 2 or 3 hours and it was fine, even at the lower temperatures. This was all done under cover, but outside. The need to take advantage of the occasional days of good temperatures was a strong point in favor of using Bristol finish. It was slower to dry fully, but not excessively so. I only mixed what I needed, so I have no good feel for pot life.
Someone did mention that it was runny and sloppy, but I found it no more so than most every other product I've used. However, it did surprise me when I finished the 4th coat on the main just before dark. I had brushed it out pretty well, but apparently it had a few too many hours to set up given the falling temperatures. Come morning the bottom side was filled with little 'icicles' of that very expensive BF. I sliced them off with a razor blade, wiped them well with lacquer thinner, let it all set in the sun for a couple of days, then lightly sanded and added a 5th coat just along that surface. Surprizingly it came up fine. Not sure I would have gotten away with that with a varnish, but then I would not have been varnishing at dusk.
I would be careful using this stuff inside, it put up a pretty good vapor. However it did clean up well with Lacquer thinner. Some folks around here love the stuff, but we'll see.
I'll send a picture when I figure out how to do that...