That sounds logical. The dial on top of the head will tell you how much power you lose in the 'W' setting. I don't know whether or not the 60 CT-2 could keep up with the EOS3 at full speed. Try it without any film in.
(Later edit: Using it in auto with a wide aperture setting and fast film may bring the recycle time down enough to achieve the same result while retaining auto operation.)
There is also a tele-computer thing (I forget the number) that gives you a lot more control over the CT60 in manual and auto modes. You may be interested in looking for one of those. I use mine fairly often. The other bells and whistles include a bounce card that looks like it belongs on a Soyuz and a monster tele lens.
I don't know how easy it is to find SCA500 modules (not SCA300), but there was a Canon one made that might give you TTL with the EOS3. I'm not sure, because the most up-to-date Canon that I am familiar with is my T90. Or is it a T34?
PS the other scale you refer to is the maximum distance in metres for direct flash at that speed and aperture.