I don't think that the Cavalry Charge rules, specifically the Musketeer's Support Fire rule, reflects 17th century warfare as well as it does later periods when bayonets have replaced pikes, and almost every infantry element had firearms. In this period the majority of the infantry units were combined arms of pikes and shot which were trained to support each other. Cavalry shouldn't be allowed to charge unshaken pike elements at all. Also, the Musketeer's Support rule should be based on the other elements in the defending element's unit, and not the one element itself. If a non-pike element is defending from a cavalry charge and there is a unshaken pike element in the unit then the support test should be taken as written. This simulates the shot elements having the time to avoid the cavalry charge and deploy under or behind the pikes. Firearm infantry were very vulnerable to a cavalry charge, which is why they had supporting pikes in their unit. Bayonets changed all of that.
It also looks as if dragoons are classed as cavalry, but in the 17th century they were infantry with firearms, mounted on nags, who fought on foot and never charged. In the 18th century dragoons became medium cavalry, so including them then makes sense then, but not here.