It is tricky, but like people have said, to get this stall you use up 6 card places in your deck, 6 places for permanents (quite a bit I think!) and also you need to actually play all 6...
The only difference between OldTrees' table and original, is that as a single card, it no longer differentiates that much between HP of creatures until you stack....35% for creatures with lots of HP isn't that much, whilst already 20% for those with 1HP...I know this is probably needed to make it stackable, but was kinda going for more extreme if possible, perhaps a middle between it all would be best, would need some careful finalisation!
As to momentum, when looking at the wording "The damage caused by ____ can not be reduced.....etc" - I guess it will bypass Thicket whether I like it or not!