Tony,
I was talking to a guy at the stand at Tinnie and Tackle show where I bought these jetheads and hexheads and he reckons they should break the surface every 3 seconds - can't remember his name but he used to be on Brownies Coast Watch and is sort of "famous" but as I don't watch TV it meant nothing to me.T&T Show.JPG
Speeds I troll jetheads and hexheads are 12kph to 18kph as they seem to blow out of the water over 20kph.
Having said that I am geared up now for high-speed trolling 30-37kph where you troll a 1kg weight 10m in front of lure to keep it in the water
With the teaser just put 2m of heavy multi-strand wire on it so the razor gang only scratch it.
Put the teaser near enough to the lure so when attracted to the teaser they find the lure - if two lures at say 30m and 60m then teaser at 45m.