Ordered a few red filters (2*52mm and 1*77mm) to work with PST etalon on smaller telescopes like my Borg 45ED and Ranger, the largest one I can find it still smaller than my C5, otherwise, it could be great. These filters will hopefully arrive within next week.
Still need to find good way to mount the 6.5" red aerial camera filter on my C5.
The PST etalon adapters should arrive within next week, too. I shall find chance to try double stacking two PST etalons together with my friend.
For remote operation, I've just ordered another Meade DSX-90 mount, this time it's brand new and come with a cradle for mounting.