You mentioned that you were considering using red instead of white so that you could use Goblin Welder. You also made mention of several creatures that you thought would be suboptimal without Tinker. I think that you could make more effective use of Duplicant and Triskelion with neither Tinker nor Goblin Welder by making use of Skeleton Shard. You have an abundance of mana and you could replace 4 Plains with Caves of Koilos, Scrubland, etc. if paying

to activate it bothers you. To make the most of this recursion engine, it may even be worthwhile to make space for a Spawning Pit or two.