Thanks for the information guys.
A few years ago I took photographs (for a newspaper article) of an Opel Kadett (early 70s type) which had been prepared for track racing timed events. The owner was quite obsessed with attention to detail primarily in weight saving. He had uprated the brakes and talked about the importance of considering the unsprung weight, especially on a car lightened as much as his being used for racing against the clock, a few fractions of a second gained or lost here or there can make quite a difference. On it he had used Volvo calipers (440 I think) on the front because they were 4 piston type and fairly compact (lighter weight).
I fitted a Trackerjack Sierra caliper conversion to my Dolomite. Before doing so I looked at the brackets and realised that it is possible to fit the calipers to be leading or trailing. I stuck with the trailing option because of the unsprung weight issue the Opel owner had explained. Looking at back wheel drive cars parked locally (BMW and Mercedes) I observed that all had trailing front calipers so figured that this confirmed what must be the way to go.
Another car I uprated the front brakes on was a T2500S, to which I fitted Jaguar XJ calipers. These 4 piston XJ calipers are much heavier than the original Triumph 2 piston type. This weight difference is noticeable in the steering at first but you get used to it.
Sometimes we can get bogged down discussing theoretical possibilities. Look at the achievements of the world's greatest snooker player Stephen Hendry, he won seven World Championships playing with the world's worst cue (it was badly warped).
How was that possible
?