WS64 thats a nifty tab transposer you have!
anyway, idk if this has been shared yet, but what about just barring the whole first fret? Does that make it more comfortable for you? When I first started out on the ukulele I played Bb by doing the whole bar instead of just the first 2 strings on the first fret. Then later I saw advanced players doing it like that so I just copied them.