Okay so
Since you are talking about getting 4.0 aps I'm assuming you're demon (2.86 base edges +spark) ?
An acceptable build would be minimum dex for edges and the rest in strength. However, when you turn a class into aps, critical rate becomes much more important..so an extra 50-60 dex + a crit shard ( or two shards, but that will counter what i'm going to say after) would help out.
You can maximize your damage by using the best atk type S cards, nuema, runes, and meridian. '-'
Seekers do not get much aps speed. Demon sparks aside, you'd only have two ways of increasing your aps- windshield from your genie, and quicken sacred stone imbued into your weapon. (it would nerf the aps you get from demon spark if you are)
puzzle cube mdef and warsong belt mdef are a must, along with a physical version of ONE of the two incase you may need it against a physical class.
And for the r8/dragon sets, the only part you can get aps on are the wrists, x2 wrists would not make a difference in your speed but x3 interval wrists would put you at 3.3 base (r8 wrist and rest of gear being dragon)
Hope this is what you were looking for, good luck. '-'