Hi Real Deal..

first time i've read this thread and i like your way of thinking...
I take it you rating the race your betting in..if so and especially if the field is only small you might try something like this

your selection or banker
plus the next 2 or even 3 next rated selections on the 2nd and 3rd lines ..
also have a level stake..
say 100
if the selection and the field for a 1/2 costs 50
id then have another tri with my selection and my next 2 rated selctions
for 25 ..wich costs 50

100 total..

this way you have both scenarios covered...

this is the way i do it ..although twice as much on Brissie racing and its shown a huge profit...the strikerate isn't fantastic but then again i rarely back favourites and never short favs...but the monster tris i have gotten more than make up for the run of outs..

Good luck with the system...its good to see someone having a go at trifectas...
the same system can work for 1st4's as well