Hi George, that's looking pretty good for that continent, although i'm viewing it on my phone so I can't see stuff like rivers and the smaller details. For celestia, you need the whole thing in equirectangular projection, which is difficult (at least for me) to draw because it gets really stretched near the poles. What I would do is cheat a bit; call your eventual stitched together map a mercator and then use an app/plugin like flexify 2 (a google search will get you to the flaming pear product page and there's a free trial) to go from mercator to equirectangular. But you'll still be missing the poles, so I'd grab one of the good Earth equirectangular illustrations from the motherlode (google "celestia motherlode" to find it) and blend together its poles and your reprojected middle. it'll be quite the undertaking, fair warning
Sorry for lack of links; on the phone it's hard to grab them and get back to the post.