SHA clone will work just fine. It should take a smaller main jet than the stock carb since it is a bigger carb/venturi. SHA jets or qt main jets will work in the SHA clone. There's at least one clone, I believe it is the DAKAR clone that has an air/fuel mixture screw as well as the throttle stop screw. This is nice compared to regular SHA carbs.
The SHA carb will fit right over the stock intake. You will need an o-ring between the intake and where it fits into the carb. Go to the hardware store and get one if necessary.
Stock throttle cable should work fine with the SHA carb although double check and make sure the stock throttle cable pulls the slide all the way up. Oh yeah, I've always had to take the brass adjuster that fits on the chamber cap off the stock qt carb and put it in the SHA carb to get the throttle cable length right. The metal cable tube/guide that comes with the SHA is way too long.
You will need a 60mm air filter for that carb. I've bought the absolute cheapest SHA clones and run several on several qt50s. Amazon had some with air filter for $17 shipped. Never had any issues. (edited)