Dave, I see you running 6v system from your powerbox.. I´ll assume that the servos I look at, will do just perfectly. HV are a bit expensive at least when it comes to servos with good reputation/brand and especially here in Sweden .Ripmax´s instruction recommends their own Quartz brand, wich to me looks like some budget servos equivalent to Emax ones.
I´ll go with the MKS I´ve found due good price and their availability at the onlineshop.
2200 and 1600 lipos them I have some of