Point league setups vary, so let's look at yours:
Shutouts are impossible to predict, so ignore them.
The key ratio is SV versus GA. In your league a goalie letting in one goal on 6 shots gets zero points (.6+.6+.6+.6+.6-3=0) so any average performance of a .900 SV% is worth 2.4 points (5.4 -3) per 10 shots faced. So that's a nice positive, and if they get the win even better.
However, skaters are very highly scored 6 for a G, 4 for an A, and shots and blocks add up fast.
I'd look to use only 2 goalies, and go with another skater. It might be very viable to go with less. There is a poster out here who was using a zero goalie strategy in a league, because goalie scoring was so harsh, many games ended up very near zero.