it is hard to expect the number of crossover. it depends on the distance between genes on chromosome (or markers on linkage group). for instance, if two genes are very close, they tend to be co-inherited in next generation, while, if the are far away from each other with a distance which allows the crossover to occur, the number of single or double crossover will be increased. The best way is to check the double crossover between markers in each linkage group after mapping.  

I am not a specialist of wheat. The number of crossover will depend on the distance between your parental lines. If they are very closed you will get your RILs at the next generation. If they are very far, you will do your crossing for more generations before avoiding the barrier of sterility. In this case, you need to confirm the target gene presence at each generation using markers.

One can not expect any specific number of crossovers without having the idea, how close or farther apart genes are located on any chromosome? As it depends on the distance between genes. one should map first to have an idea.