Higher success chance makes a big difference when you're trying to do the tradeskill missions.
I can think of four tradeskill specs I would go with:
Harvesting: Ample Harvest 5, 15 filler points, and Trim Reaver 5
Missions: Swift Creation 5, High Quality Materials 5, Effective Method 5, Advantageous Practice 5, Resilient Materials 5. You simply don't need Conservation of Mass 5 for missions, as you have an unlimited number of items.
Writs: Swift Creation 5, High Quality Materials 5, Effective Method 5, Advantageous Practice 5, Rapid Manufacturing 5. Cranking out combines as quickly as possible will greatly speed up writs, and the less you have to deal with failures the better.
Mastercrafted Crafting: Swift Creation 5, High Quality Materials 5, Effective Method 5, Advantageous Practice 5, Conservation of Mass 5. A chance not to consume the rare is a good thing.