Your probably not going to get many hits on this one! Burns pickups are a very small niche. The tri-sonics have a bottom loaded ceramic magnet with flush poles. In terms of ohm ratings they aren't much more than a strat pickup. They are of a different size though so you need a custom pickguard to use them. I guess you can get tri-sonics from the SD custom shop, kent armstrong makes the burns pickups that are used on the current burns guitars. This guy is considered the tri-sonic guru http://www.adeson.co.uk/ maybe he can answer your questions.
I have never tried the burns pickups. Although I do have the Dimarzio Brian May set. The Dimarzio set is regular strat size.