Interesting you should ask. I have a coupled resonator for 17M off an 80M dipole at 70', and a 17M H DoubleBay pointed E/W, top at about 60'. According to 4NEC2 it has a fairly low elevation angle, like 20° and it did the best. I have good luck with that HDB on long path prop, I also have HDB and dipoles from 17 through 6M, and I pick and choose which works best if I have the opportunity. Sometimes it's hard to tell, sometimes it's night and day. The HDB's work best on 17, 15 and 12 for long haul recently. Sometimes 10, but that band is just starting. It's been a while.