I don’t think it matters if they mix; I add the sealant first and then just rub the beads with soapy water with my fingers.
(I didn’t realize there was an issue with sealant and co2. I guess I rarely use cartridges but will have to remember to update the sealant after doing so.)
I buy the yellow tape (Tesa, but same tape as Stans) in big rolls now. I have a big roll of the 25mm stuff if you find you need to tape the rims. The 25mm should be good for rims over 17mm internal width or so (?)
For those using soapy water to ease things along (and I also read on some MTB forum of people using butter on the tire bead) do you get them seated “wet” and then remove the valve core and add the sealant or do you have the sealant in there before adding the soapy water lube or does it not matter if you mix some of the soap water w/ the sealant?
I seat them with the soapy water (so inflate until ping) and then remove valve core and add sealant. I’ve only done one set of tires ever, though.