20D Colour Temp & Flash

I'm about to use my 20D with my Bowens flash heads for a portrait session.

The standard colour temp on the camera is set 5200K - Do I need to change the setting in the studio?

Yes - Bowens gives their colour temperature at 5800K. Electronic flash in general is cooler than daylight.

Do a test shoot without any type of colour temperature "corrections".

You may well need to adjust this later, but how do you correct things when you don't know if there's anything to correct in the first place? This would be exactly like salting your food before you taste it.

Yes: Test, evaluate, correct.

No: Correct, test, evaluate

You'll get the most accurate colours if you use custom white balance. On the 10D, and it's probably the same on the 20D, you do this by making a photo of a white or neutral gray object under the lighting that you want to use, and in the menu of the camera set the white balance to Custom, and choose the image of the neutral object as the reference point - look it up in the manual of your 20D.