Mono camera and scope pair

[JayPea]

After a while dabbling with a dslr and an achromatic refractor I'm after a recommended mono camera and ed refractor pair to upgrade to. I have guiding and an heq5 pro. I'm looking at mono images as I'm in a very light polluted  garden. Budget £1300-£1500 for everything (camera, filter wheel, Ha filter, connectors/adaptors, and scope.). Not bothered about RGB initially and I have 1.25 light pollution filters already.

I'll be photographing the usual suspects, pinwheel, dumbell, whirlpool, Orion, etc. I assume wider fov would be out for these small chips with most scopes.

The zwo 178 mono looks to be my favourite at £375. It looks like it would go well with a 300mm focal length/f4 scope but I can't  find one. So the Altair Astro 80ed-r looks good at £600 - top end of budet for scope. Plus a wheel and Ha (75 + 118). I guess a reducer £75,  is a 0.6 too much of a hit on the optical quality even on a small chip? Maybe their 72ed-r would be better but I wasn't sure that had a good reputation. 

Does anyone recommend a proven mono camera/filter/lens combination?

I do have loads of Nikon glass but I'm not convinced i can get the mono cameras with a filter attached and meet the back focus so I think I need a scope.

 Thanks, John