In my trifectas i save the last spot.for the best barrier horse..regardless of what it is paying..
Top line 3 (my selection,Highest Zip, Favourite)
2nd and 3rd line 6 (As above, next 2 in betting, then best barrier)
if my horse is the favourite
then
Top line 2 (my selection,highest Zip)
2nd and 3rd line 7 (next 4 in betting,then best barrier)