A good shielder is a dead shielder (archerĀ“s speech).
Depends mainly on your fighting style, if you like to dance and strike fast your enemy go for a 15/21 build with ps5 ath,shld,wm 7, if you like to strike hard, go for 24/15 with ps8, ath, shd, wm 5. You can go for 18/18 with 6 in skills.
Now some build give you more point like 21/15, which let you 7 skill points for IF or riding (or throwing but you need to splitt wpf).