Ten years on (!) from The Mosses and Liverworts of Carmarthenshire and tetrad coverage is now much more complete in VC44. I have visited all but 103 of the county's 680 tetrads. The areas of poor coverage are still the far west and mid-northeast: basically any light blue or light green dots are very under-recorded; dark green, brown or yellow are OK.
So lots still to do, but little opportunity. It's interesting to compare Barry's SN60 with 'my' SN50: 60 to 80 is probably a realistic target for each tetrad, with 100 for the richer squares.