Stephen,
Yep you can use the tripod as is as long as you have the drop in plate with the thread to the camera. That is how I use mine mostly, at an extreme angle you might be wanting a bit more clearance but there is no real problem and if you need it then just bite the bullet and get a second ball-head.
I also have the same Manfrotto 494RC but I have never tried it on the Polarie, it does say it can handle the weight of the camera but it does seem a bit small.
I use one of these and it's perfect really.
http://www.teleskop-express.de/shop/...belastbar.html