You can wear a pelham, but most riding club horse classes do state snaffle mouth and no spurs. I have stewarded for lots of these classes, and in general the judges do seem to prefer and place higher those in snaffle bits. In general they are looking for a horse that most people could ride and would be capable of doing all riding club activities - i.e. something that is not going to be too strong and needs a strong bit to keep it under control. I would always go for a snaffle