It has been done. Could've gone further and I wouldn't have lost but I proved what I wanted. I was able to stop aiming and just click on cards and win! 
The general build (I kinda just switched out 1 artifact a lot)
We're so glad you really enjoyed playing our game, and for a whole hour! And thanks for sharing your tips and strategies! The minion build is definitely powerful, though it seems you never had the chance to get the Rite of the Red Ash card from the Ash dude (lol), which is basically the best one.
It was fun seeing how you interpret the drop rates, but one thing I'd like to clear up is about the artifact's boss buff. All bosses already start with 7 artifacts, and all artifacts (except the useless pebble) apply a buff based on whether it's held by the player or by a boss. Bosses already benefit from the artifacts they hold. So for example, exchanging the gravedigger's obsidian spade (boss buff is +40% area and +20% bolus area) with your useless pebble makes his attacks smaller as he now has a useless pebble (which does nothing) instead of the spade. But on the other hand, exchanging the spade that the player now has for, say, the ceremonial shears held by the hairbeast (which only has a boss buff of +25% area) will just give the hairbeast an extra +15% area and +20% bolus area.
Also, you thought the spade drops more from the gravedigger, but it's because it's actually exclusively his. Bosses have at least one exclusive artifact each that are a little bit more powerful than others.
Thanks again for taking the time to play and leaving this comment! It means a lot!