I would honestly play white here. Perfect mana isn't going to be a problem that often considering how much of your deck is colorless. A single mountain and you're fine for the most part. And you're playing some bad cards over some great white.

If you want to try staying with 15 lands, I'd cut the two Self-Assembler and the two Foundry Assemblers for Airdrop, Propeller, Caught in the Brights, and maybe Deadeye Harpooner though that slot could be a flex. You also aren't actually that into the improvise plan. You have the dragon, which is great, the Giant, which is good, and two Foundry Assemblers, which are pretty bad.

Personally I'd cut the Dreadnaught here regardless. You two creatures with CMC three or less that have three power (including Aether Chaser since you can normally easily swing in and make a servo). It is a place to dump all of your smaller creatures if you need to. But tapping three creatures in many circumstances will leave you very open. I think I'd play Precise Strike. I've ended up liking it as a combat trick.