at level 30 you can't make any good 1h shielder build apart from 18 18; the perfect level cap is 31, every 2h/pole build fits perfectly at 31 (e.g. 21 18 7 IF 7 PS 6 ath 6 wpm)
Hmm, I've been playing shielder all my life (well 3 years) and there are in fact many good builds at level 30! 18/18 is a good balanced build...but you can also do:
21/15 (5 ath is enough)
15/21 (5 PS is enough, use a blunt/pierce)
and my favorite:
21/18 (If you have nice armor, you don't need IF as much)
So, depending on your equipment and if you have looms, you can easily do 4 builds! You can also have success with more extreme builds, but these are tried and true.