Gents,
For what its worth, here is a comparison of the 2 methods for races run on Mon 9 Jun - using NSW TAB divs.

CF and $ (selected night before) 3 bets for 2 winners and a 3rd
Out $3 - return for Win $5.60 / Pl out $3 return $3.70.
1 x 6 - Outlay $21 Return $27.80 = 32.3 percent profit.

CF and PR after scratchings (therefore only selected on raceday) using same rules as operated last Saturday. 7 bets for 5 winners a 3rd and 1 unplaced
Out $7 - return for win $13.70 / Pl out $7 return 7.80.
1 x 6 - Outlay $49 Return $60.50 = 23.4 percent profit.

Cheers.....Mancunian