Grunch, just giving some thoughts on dredge now that I'm taking a break from the deck
In my opinion the 15 card transformational dark depths plan is outdated. Played that version to a win in a format challenge a while back, but now that many shops lists are on ghost quarter MD + karakas SB it is much less exciting. Have not tested the anti-hate+angler/hollow one package, but on paper it seems awesome vs shops. Your combo matchup is already pretty good if you MD 12x FOW/Misstep/Mindbreak, and the dark depths plan was at its best vs shops anyway. Unfortunately I don't think now is a great time to be playing dredge, as UR delver has been pushed out of the format, and most control decks have some sort of tinker combo package.
As a general rule here is how I have historically sideboarded with my old decklist, even though its outdated I think shows the general principles of siding with transform dredge. Side in everything, cut cards that speed up your clock, cut dead cards, 10 dredgers minimum and that is pushing itt...
One Note: Therapy is horrible vs shops, can't be cast half the time and does nothing when cast. Misstep is horrific vs shops game 1 but fantastic post-sideboard, hits their 4x Grafdigger's Cage and Relic. Never cut it ever ever ever.
+15 Card Transform
-1 Dread Return
-3 Dread Return
+14 no portal (think sometimes I boarded slightly diff, cutting some FOWs leaving in extra dredgers)
Imo the immediate future of dredge has us swinging back around to the faster leaner versions of dredge, similar to this version from 2 yrs ago. I would prob cut the leylines from MD unmask, cut some mana perhaps, and modernize the SB with creature package and 4 mindbreak either side or main