Red Single Mode Diode?

Those single mode 638nm reds are going to cost you out the nose and you'll have to beam-combine them in a knife-edge array to get any kind of power that could reasonably balance out a 200mW green. I would try and work with the 500mW variants as best you can.

Oh, and Thorlabs isn't overpriced, you're just used to low-ball prices. Keep your eyes open for optics on eBay. I've gotten some good deals.

If you want to dabble in beam correction, read some of the threads in the optics forum. We're all trying to make these wide-beamed 638nm lasers work well.

There are quite a few proven correction setups for the 300mW and 500mW diodes. See this thread as a start. You may want to start at the end as it is really long. Some prefer the 300mW and some prefer the 500mW ones but I just think it depends on which correction setup you are using.

Mitsubishi ML520G71...Red Holy Grail or Flashlight Fail ??