I don’t know if I would assign percentages to just how important stuff is.
The fact is that tire choice IS important. Period. No amount of fitness and skill are going to make up for anyone bringing Dunes or Chicanes to a mudfest.
It’s not that tire choice is going to win us races all the time, but tire choice 
percent is going to have an effect on your race. Saying it won’t is just ignoring physics.
Two thoughts.
a large proportion of this forum is dedicated to power/fitness. It’s not like we’re only talking about tyres.
if the OP doesn’t t have a cyclo-cross tyre and is thinking of buying for non-UCI use, it’s perfectly reasonable to wonder what width to get.
My own answer to that question would be a set of intermediates in a 36-38 width. They’ll be grippier and more comfortable but still have mud clearance and do better double duty off the race course. Then a set of muds, perhaps a bit narrower for more clearance. I agree that gets you 95% of the way. Then perhaps a set of file treads because experimenting is fun.
If you read the quote in my response only and not the rest of the conversation my response makes more sense. I didn’t make my way through the rest of the conversation yet and thought you were just saying that tires don’t really make that much of a difference and was responding to that.
I see now later that you are saying a Mud vs Mud, Dry vs Dry or Intermediate vs Intermediate doesn’t really contribute huge factors against each other like some make it out to be (not that a dry vs mud tire would).
I think I, too, interpreted your post wrong and could have worded my response differently. Agree that Mud v Mud and Dry v Dry are on the “doesn’t matter” list for most people.
The wider is better philosophy runs into some issues with muddier races, when the corners start getting rutty. A narrower tire is going to cut into the muck and grip more while a wide tire may sit on top of it and slide. There’s a reason some manufacturers make 30mm cross tires, esp. the mud treads. I feel like a 33mm Limus and a 38mm Grifo is a good 2-tire solution
Exactly. I would think a 2.1 Schwalbe Thunderburt would be the answer, but doesn’t meet his 47mm limit criteria. I wish my 2010 Roubaix had capacity for larger tires (greater than 28mm).
A week of riding/training and one race down with the Vittoria 38 Mix and they are pretty dang good. Race was mostly on dirt, some singletrack, fast ripping sketchy downs with sand, and grass and was very confidence inspiring. Would recommend.
Baby limus has been trash on off cambers for me, when the off camber is steep it seems like the side lugs just let go and all of a sudden my back wheel is sliding away. Grifo H TLRs seem way better for that.
Running a Pirelli Cinturato H 35 on the front of my ss after cutting a baby limus. Pretty impressed with it so far, need to give it a try on the back.
There’s no doubt that I’ve found 2.1 Thunder Burts to be faster than I expected, fun to ride and preferred on singletrack and rougher gravel. An MTB tire is not faster on grass and anyone who’s ridden across a grass field, MTB tires are really draggy. On a CX course a mix tire on front for corner grip, with a less aggressive tire on the rear is fastest in 38-40. Vittoria Terreno Mix and Dry or Challenge Grifo/Dune