I don't know about the keycool's ones, but some key caps I ordered on the internet (not to mention the site) like the "gold zync" one, are a bit too "high" (can't figure out the good adj to use here) and I didn't find any place where they could fit good on mine blackwidow (sad because I paid about 50$ to have the starcraft key caps (race + leagues)).
also I got a friend that ordered a space bar on the WASD site, and it was not on the good size for his blackwidow (can't remember if it was too big or too small).
So be careful if you order some keys for your blackwidow, I don't want to say that you don't have to make it, because I only had problems with the Zync ones, and the other key caps are awesome!
I hope I helped you, if not, sorry like that you have my opinion about it