Hi,
The OP asked for the differences between Permalyn and Tried and True. I've used them all at some point in time. Permalyn contains some sort of compound very much like polyurethane. It is easier to use than Tried and True and more forgiving when applying. It is also as weather resistant as you can find without applying an epoxy finish. However, it builds up quickly and can have a glossy plastic look unless you take care applying it and rubbing it back. Tried and True linseed oil varnish is as close to a historically correct finish as you can get without making your own. It is a linseed oil and varnish mix. You have to apply it very sparingly and wipe off any excess. It must dry fully between coats. If you don't do that it will be soft and seem like it never dries. However, it produces a very fine and historically accurate looking finish, more so than Permalyn. Both benefit from first coats that are thinned so they penetrate a little deeper and help seal the wood a little better. Nonetheless, don't fall for any fairy tale about "deep" penetration of any finish.
dave