Brother gauis... LPI is the same as US Mesh. So 60 LPI = 60 Mesh = 250 microns (u, or actually greek mu) for the top screen. Second screen is ~85 LPI= 85 Mesh = 160 microns...
For the metric measurements (microns), they list the hole size, so the bigger the number the bigger the hole.
For the LPI/mesh numbers, the list the number of lines per inch, so the larger the number, the more mesh threads/inch, and the smaller the holes.
For your across the pond measure with the T and HD... It measure lines per centimeter, so the equivalent should certainly be less than the lpi/us mesh number like psuper stated.
As far as your bubble bags, as an example... 25u, 72u, 120u, 160u, 220u going from smallest to largest... They would seem reversed going with mesh sizes 400+ would be your smallest, 200, 120, 85, 65 (numbers are approximate, but demonstrate the idea)...
As far as your local screen suppliers... If it were me, I'd probably grab the 24HD and 32T from your site you linked if we're talking about DSW's method... 32 is a little bigger than DSW's screen, while 39 is a bit smaller, so tough choice between those two.