Unless you have half a million or more to invest I wouldn't bother about spreading yourself so thin. You get almost as much diversification by just going a third each on Total Stock Market Index (VTSMX), Total International Stock Market Index (VGTSX) and Total Bond Market Index (VBMFX).

Or other proportions if you prefer.

If you have $100,000 to invest then with your spread you'd only have $5,000 in the REIT Index. On the other hand if you have $500k+ you'd have $25,000 in your smallest investment, which could be big enough to matter.

My recommendation would be to use the three funds I mentioned above, and add one more fund per $50k (or $100k) above that.