Here is my current list, adjusted for having to deal with Lavinia, it is devoid of any "cute" cards and seems to be a pretty solid performer for me at the moment.
Mana sources (29)
Business/Good Stuff (4)
I put the red splash back in so i can play Pyroblast in the sideboard, and while doing that, why not add Wheel back in? I have cut Defense Grids in the sideboard, since they kind of desynergize with Pyroblast. While playing with this list, be careful to only fetch for your Badlands when you intend on using it immediatly, getting it wastlanded is pretty devestating considering this and Ruby are the only consistent red sources in the Deck. Currently Pyroblast has both been great as removal and an kind of unexpected "got you" card sometimes, but ofcourse MM is its biggest weakness, try to clear the way with discard spells before using it if you want to remove a problematic threat with it.
I have had a couple of situations in which an LED in the deck would open up an easy win instead of doing nothing, i might want to add it in again, especially now with Wheel back in the mix.
Out - 2 Defense Grid, 1 Thoughtseize, 4 Duress.
In - 3 Hurkyl's Recall, 1 Rebuild, 1 Echoing Truth, 1 Tinker, 1 Blightsteel Colossus
On the play you might want to consider not cutting that many discard spells, on the draw, throw them out. Cutting a Bargain is a good option if you need an additional slot open since you most likely will suffer some damage before going off.
Out - 1 Hurkyl's Recall, 1 Wheel of Fortune, 1 Cabal Ritual
In - 3 Pyroblast
If they play Lavinia you also want to bring in Echoing Truth, if they do not play any permanent hate cards, consider cutting Chain of Vapor over Cabal Ritual. You can consider cutting a Bargain if they play aggressive and you tend to take some damage while still setting up.
See above, with the exception that you want to bring in Sadistic Sacrement if they play less than 3 actual win conditions (Some only play Tendrils, Mentor and Key for example). I dont recommend brining it in if they have more than three. Look out for Blightsteel, Jace, Tezzeret, Karn and the likes.
If pitch Dredge
Out - 1 Wheel of Fortune, 1 Hurkyl's Recall, 1 Chain of Vapor, 1 Thoughtseize
In - 4 Leyline of the Void
If no pitch:
Out - 1 Duress, 3 Thoughtseize, 2 Defense Grid, 1 Wheel of Fortune
In - 1 Tinker, 1 Blightsteel Colossus, 1 Echoing Truth, 4 Leyline of the Void
Out - 1 Wheel of Fortune, 1 Hurkyl's Recall, 1 Yawgmoth's Bargain, 1 Chain of Vapor, 1 Cabal Ritual
In - 3 Pyroblast, 1 Tinker, 1 Blightsteel Colossus
If they play Lavinia, Thalia, Canonist, Leovold, Stoney Silence, Null Rod or other probelmatic permanents, consider leaving in Hurkyl's Recall or bringing in Echoing Truth.
Edit: Why no Leylines here? They are just not optimal, they slow down their deck, but they still have a lot of threats that ignore the leylines. I opted to go for more of a race, rather than try to slow them a bit and slowing myself in the process because of the 4 more cuts I have to make, however this is not the best way to go about it I think. The better sideboard cards against them would be tormods crypts or ravenous traps, mostly because you are not locked into boarding 4 or nothing. However, playing these cards instead of leylines will make your pitch dredge matchup much worse, leylines is without a doubt the best card against that strategy. I think it depends on what deck is more prevalent in your meta.
Out - 2 Defense Grid, 4 Duress
In - 1 Tinker, 1 Blightsteel Colossus, 1 Echoing Truth, 3 Hurkyl's Recall
Here the Hurkyl's mostly comes in because having them is better than the other options, if they play Null Rod - good - if they dont its just mana/storm acceleration. If they play blue (Lavinia) bring in 3 Pyroblasts instead.
Out - 2 Defense Grid, 1 Hurkyl's Recall
In - 1 Sadistic Sacrement, 2 Pyroblast
To be honest Pyroblast might not be the best here, the mirror mostly revolves around discard spells and beeing faster than your opponent. Pyroblast is okay, but not really incredible since most of the threats are black. You might just want to bring in Tinker/Robot to have another threat or more hurkyl's as acceleration.
I have not had a ton of testing with this list, what do you think about it and the sideboard plans? Iam considering cutting 1 pyro from the sideboard again, but iam kind of scared of Lavinia, especially now when everybody is testing her.