Bob Gamblin makes an alkyd resin that is far better than Liquin. He calls it Galkyd Lite. I suggest you check out his web site.
http://www.gamblincolors.com/
I'm pretty conservative, but I think it's probably a good idea to give your freshly dried canvas a light brushing of 1/2 GALKYD LITE and 1/2 Odorless Mineral Spirits. It dries in a day, will keep the painting looking fresh, will eventually bond with the paint so it can't be removed in the future.
Then if you are so lucky, you can give the painting a final coat of high end picture varnish (Gamblin's GAMVAR is the best final picture varnish in the world) after six months or so.
This varnish is reversable and can be easily removed for restoration in the future.
Bill