Don't cut anything..... you just need to move your secondary mirror... but the primary mirror is set to the length it was made for. It will be out of focus if you get anything wrong and the seconday screw holes need to me 0.0000001 correct just like anything astronomy. it's not worth it, get a low profile focuser. It will work just fine, i'm not sure about filter wheels alltho I have seen pictured of people using live view cameras not DSLRS.
Starlight instruments or moonlite low profile will work. but news get flex ... thin you do get a focuser clamp for both sides which helps, but you will never get a perfect balance unless you use liveview, and even then you will need to plan your viewing sessions for best angles to what your gear is setup. MISSIONS. stay refractor and look for a second hand EQ5 your mount is equiv to a celestron AVX not much good past 200-300mm focal length... With what you have here from a year ago try to stay native focal length, less errors and stay bloating due to magnification.