Usual warning here, don't do any of this unless you are sure about what you are doing.
This is our most recent experiment for Ha imaging. We removed the Quark filter from our Daystar Solar Scout 60 and 3D printed an adapter to an M42 thread to mount it on our 72ED, with the addition of an ERF in front of the Quark. The result gives a focal ratio of 24.36 which is getting better for the Quark than the 15.5 of the Scout. There are a number of issues still to resolve but we are happy with our first attempt at imaging with this set up.