You can do both to a similar standard if you give both equal time throughout the year. I tend to do FT through the winter and HFT through summer. What I found was that at the beginning of each respective season I'd be pretty poor at each discipline. My scores would ramp up just as the season was coming to a close. Then it was back to square one with the other discipline.
It's a select band that can do both to an excellent standard. I'd go so far as saying that there aren't that many that can do both to the same standard even if that standard isn't particularly good!
SFT should be a different ball game and I can't see why many HFT shooters don't give it a bash, especially when they are members of clubs that do both FT and HFT. Yes, it's not perfect practice for HFT but, at very least, it'll give some rangefinding practice. If you don't want to play to achieve maximum scores then you could do most of it kneeling and get some serious kneeling practice in.