For stats, they will be based on whether you plan to go a fast attack speed or tanker build.
Normally you would get DEX to 20, STR to 30 then put the rest into VIT/AGI until you notice a large jump in the stat increase. I'd recommend maybe 20 VIT if you went AGI.
I'd get the spear accuracy, spear delay cancel and IIRC at level 34 there was a passive defense skill. Then you get SP Recovery Increase for when you're partying with druids at higher levels. You could go all the way to 50 for thrust guard or just job change now.
You'll need BOTH Knight and Dark Stalker for a proper build, so don't worry about deciding.