scurredmoney - Good question. I would suggest you analyze your dogs first, then decide if they are worth a money line play or not.
For example, if you like a 5 pt. dog and feel strongly about an outright win, then perhaps you go strictly ML bet, depending on your risk tolerance. In this case I would at least play 75% of my game wager on the ML.
If you like a 10 pt. dog but aren't so sure about an outright win, then your 1/4 -1/2 scenario might be more appropriate.
ML dogs can carry you a long way even if you are only mildly successful. You can't be too afraid to step up to the plate and play them when you've done your homework and identified a live one.
Cheers!