One camera does not fit all! You have a variety of combinations there equipment wise too. I think I would get an IMX249 sensor on USB3 to give you the 5.86um pixels suitable for the Quark and your 6" scope. This should be around the $500 line. If you can free up some more cash the IMX174 sensor will give you the benefit of faster frame rate which most definitely helps at these long focal ratios.
Given what you've got equipment wise already, i'd get a Baader solar film filter ($25) to get you into white light, seeing as we're heading to the start of a solar cycle where spots should be appearing more readily.
http://brierleyhillsolar.blogspot.co.uk/ Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
Thank you Mark!
Interestingly if I have that sensor and USB3 but it is color. I also have the basset silar film but have frankly forgotten how I used it successfully before but it is a great reminder for me!
Related question,
My wife is getting tired of me building things and my last PST mod is not behaving too well so that is why I thought I would try the quark route. I have not purchased it yet though. Would it make more sense to get a nicer camera and a BF 10 or BF 15 and finish the mod correctly??
You really need the monochrome route for solar cameras. It is likely your spacings are not right for your PST mod.
http://brierleyhillsolar.blogspot.co.uk/ Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!