Hi new thief here asking help.
S/P does not have a lot of condition damage associated with it so you’re best off going with some combination of power and crit/critdmg for offense.
Personally I went with a combination of berserker jewelry and knight armor. Berserker offers power/precision/crit damage while knight offers power/precision/toughness. My weapons are a varity of WvW weapons (For toughness, vit, and power) and berserker’s crafted weapons (For more offense).