My favorite varnish for application is now Le Tonkinois Nr. 1. Because it's an oil and resin formula, it does not have solvents to evaporate off, it simply cures. As a result, it smells good (to me) and is easy to maintain a wet edge, with no thinning needed. Seems to fill in the grain pretty easily as well. I think it holds up in the sun reasonably well also, even though you would be using for interior application.
I have used Watco teak oil for other applications. It goes on very thin, and will eventually dry hard(ish), and start to build up with multiple coats. I don't know that I would use it for interior work, though I don't think it would be too soft. It does have solvents, and would smell the place up.
I wonder if Owatrol Marine's Deks Olje would be good for interior work. I become concerned that too soft a finish will turn dirty and goopy when hand oil, oily sunscreen skin, etc. touch it... Since I haven't used it, I don't know. Stupid of me to mention it in that case
Does anyone use straight boiled linseed oil for interior work?