Not counting the 801 Pen Style DH used for many many months before using a Reo.......... But will say that I always got him low bridge attys. The standard ohm rating for those were just under or at 3.0 ohm, at the time.
I have two 801s. I like the IKV 2.0 standard (as I got 20 of them for <$1.50 a piece) but better still the IKV 1.8 Mini. I make my own Semi by cutting down the standard length. I like the Semi length best but they are no longer made. With the 801 the ohm rating acts differently than the 306 and 510. For instance, with some juices <2.0 ohm 510 or 306 might be too hot,but an 801 1.5-2.0 is great. When you go higher than 3.7volt, for 801, knock the ohm rating down as much as 0.5 to 1.5 ohm (or even down 2.0 ohm) compared to what what you ohm you would use with 510 or 306, at a particular voltage. Of course, type of juice has a large influence on what ohm to use.
Alice