You should have a chart to evaluate which is better, the ML or the spread at various vigs.
A good back of the envelope way is to use 8 cents for each 1/2 point (not 100% correct, but good enough).
So
+3, -110
+2.5, -102
+2, +106
+1.5, +114
+1 +122
+1/2 +130
Conclusion +130 ML and +3, -110 are pretty equivalent mathematically. I'd bet the +3 to reduce variance.
Caveat: The above analysis will only work for a 1-4 point dog. And it is off by a few pennies. But close enough.
With free 1/2, reduced vigs, etc. it is VERY rare for an offshore bettor to get a ML that is better than a game line, but it does happen on some games, particarly +1.5 and +2 games.