If that's the first time you've put synchromesh in, I'd do it again and make sure you flush it well with at least a quart. Just run it through the tranny. If your synchros are definitely on the way out, you can have the transmission rebuilt.

Contact Jerry to have it done locally. If it were me, I'd buy a spare tranny and have it rebuilt, and when your current transmission is bad enough, swap it out and rebuilt it as well.