If the 20D doesn't have live view you'll need to have a lens calibrated since IR doesn't focus at the same point as visible light.
Agreed about the calibration if you do not have live view. I went this route myself (Nikon D7000 converted when I upgraded to the D700). If you already have a collection of lenses and a spare DSLR body, especially if you are used to using that body, I really recommend you go that route.
Another option is the "old fashioned " way as we used to do in the days of film (HIE, etc). I still use a manual focus Nikkor (24mm, F2,8) as my favourite lens overall. It has the red dot on it for IR focusing, and on a wide angle lens, you get it right most of the time. But in telephoto, you need live view or calibration to be sure.
Couple more things, that may or may not help. First off, a lot of "experts" out there may tell you this or that lens is not useable in IR. for example, my favourite lens above is listed on some websites as no good for IR, but you have to test and try for yourself.
Secondly, I have been testing out Silver Efex pro, and I agree, I love it so far. Likely will end up buying it. However, it is a bit of money. I am finding that the latest Corel Paint Shop Pro, 64 bit version, for the money, is fantastic.
Attached are two HDR images I just shot for fun last weekend. The first in Corel, the second in Lightroom/Silver Efex. Remember, the Corel program by itself is about a third of the cost of Lightroom/SFX pro together.
enjoy