I understand the hs-56 will work fine, but will the hs-55 work fine as will compared to hs 56?
Nope. The HS55 is not up to the job. The centering is too poor on the HS55, and the cyclic control is one place where slop is not acceptable.
See if you can exchange the 3 cyclic servos they sold you for 3 matched ones. HS56 will work well. HS65 will work well.
Vince