So to start, cut 1 Orzhov Basilica for 1 more Swamp. 4x Bouncelands was a bit too heavy in testing, often ended up with 2x in opening hand that was otherwise good. They help 22 lands feel like 24 in late game, but can ruin openers when they're alone. Trying out 3x for now.
I have an option of adding either Thorn of the Black Rose or Palace Sentinels. I'm leaning towards Sentinels as I just value that bolstered statline more than deathtouch in a deck like this, but I'm not totally sure - that deathtouch might protect the crown just a bit too well. The extra B devotion from Thorn matters sometimes too with Gary, but that might not be so significant.
I'd also like to consider going up to 4x Duress, either all in main (less likely) or split 2/2 between main and side (more likely), but I'm not sure what to remove. I'm going to need to reevaluate my sideboard options soon.
Finally, 2x Gurmag Angler might want to be 3x Gurmag Angler. I could cut 1x Gary for Gurmag, and the remaining 2x Gary for 2x Palace Sentinel, but that feels like a test to perform after the other changes are made and tested. Too many variables swapped at once muddles results, so I'll probably revisit this.