Probably All At Wrong Scale..
search for "scale" in http://mickkn.mooo.com/convert/ .. 0 hits.
Oops. Q3 player eye height is higher than Quake.. so all these maps will feel bigger in quake than they did in Q3. Thus they are not 1:1 conversions.
Stick with q3dm6ish, I say :P
I tried out the ones that are labeled as "Finished" in the original post and all had been scaled down pretty well, fortunately :)