I am new to cyclocross. I found a high end cyclocross bike at a great price and am considering a purchase. But, I am concerned about the wheels which are tubular carbon wheels. I would like to know if it is possible to add tire sealant such as Stan's to tubular tires. The tires are Challenge Griffo. I will be using the bike on cyclocross courses and also riding through town and would like to avoid having to change the tublar tires during my ride because of a flat. I am also considering purchasing a pair of tubeless clincher wheels as a second wheelset. Thank you.