You can find this information on the wizardofodds.

I guess my point is to minimize the Books advantage as much as possible.

A straight bet (-110) has a house edge of 4.54%.

The general formula for the house edge for a random picker is 1-(w+1)/tn, where w is the winning odds on a "to one" basis, and t is the number of teams. For example, if a 3-team parlay pays 6 to 1, then the house edge is 1-(6+1)/23 = 1-(7/8) = 1/8 = 12.5%.

Following is a sample table showing the edge for parlays.

MGM-Mirage vs. Calculation Parlay Comparison
Pick MGM-Mirage Pays Calculation Pays MGM-Mirage House Edge Calculation House Edge
2 2.6 2.645 10.00% 8.88%
3 6 5.958 12.50% 13.03%
4 10 12.283 31.25% 16.98%
5 20 24.359 34.38% 20.75%
6 40 47.413 35.94% 24.36%
7 80 91.424 36.72% 27.79%
8 150 175.446 41.02% 31.08%