Just remember, gloss does not brightwork make. A guy in my club has done brightwork on his boat, and he used Epiphanes Rapid Coat. He said he put 12 or 15 coats on, but I think it looks like crap compared to my 8-9 coats of regular varnish. It didn't have the grain fill, depth, or luster. I think this depth and luster is hard to capture in photos, but here are some (attached to the post.) This is 9 coats of Pettit Captain's varnish on new mahogany. It was applied with a foam brush, with wet sanding between coats. I tried badger hair brushes, but I just can't get them clean enough to not leave flakes in the next coat. Also, I feel I can control the amount of varnish I lay down better with a foam brush. Mind you, I have used Epiphanes traditional varnish in the past, and I get the same depth and luster, though I feel it's color is darker and not as traditional amber as I would prefer.
There are no shortcuts with brightwork, except perhaps 2 coats of epoxy first. Actually, the only shortcut I've found so far is Le Tonkinois varnish. It's supposedly a very traditional formulation with just oil and resin. As such, it does not have solvent off gassing, so I feel I can keep a wet edge better than with other varnishes, without having to thin it. Also, I can use it in the house without killing myself from solvent fumes. So, while I feel I can lay it down better, it really isn't much of a shortcut, as I still need to be careful laying it on, and watch for drips and sags. The jury is out on longevity of the finish, and it might not be quite as glossy as other varnishes.
You still need a minimum of 8 coats of varnish, and some feel 10 is a good base coat. Once you have 8-10-12 coats, you should still sand lightly each season and apply 1-2 coats. Varnish is like an onion - layers of thin film, and the layers do wear off through the year. 10 coats of varnish with a coat each year should last about 10 years before you need to strip down to wood and start over again, provided moisture doesn't cause the varnish to lift or bubble. Again, this is for a traditional brightwork finish, which is what most people want to see.
If you want a really glossy finish, go for a 2 part polyurethane like Interlux Perfection. This will give you a very hard, high gloss finish, but it's difficult to repair. I think it would be best for new wood, or old wood that is very sound, dry, and will not move much.
You could also try some other miracle finishes such as Honey Teak. From what I can gather, it's an epoxy finish. But expensive.
If you go with oil, one of the best I've heard of is Semco. Other teak oils seem to wash off and wear off pretty quickly. I use Watco Teak Oil on my cedar kayak paddle, and optimally, I should put about 5 coats on several times a season depending on how much I go paddling.
Cetol is really like a lightly pigmented paint. It lays down a very thin, paint-like film, but translucent so you can still see grain below. The colored Cetol is semi-glossy. It does NOT fill the grain at all, so good sanding prep is a requirement.
Brian