We just bought our first mountain bike with tubeless tires and we also like to race Xterras. In case of a flat, I bought a tube... but what else is smart to get? It has 27.5 x 2.6 inch tires that are pretty fat, maybe "plus size". What size CO2 should we get and should we put sealant in the spare tube? It's a Giant Stance 2, btw. https://www.giant-bicycles.com/us/stance-2