The standard weight 17# recoil spring will be fine. Personally, and for your described use, I wouldn't use any spring heavier than 19#'s - Especially not with any of the factory's current extractors.
Screw, 'stock'! I run vastly superior Wolff Gunsprings' NP3-coated, non-captured, steel rods; and standard weight, (17#) Wolff springs in both of my G-21's. As a result my polymer frames vibrate far less whenever I fire; and this large caliber Glock - that has the same frame size as your pistol - smooths right out.
