I don't think you need two sediment filters.

I second (I own one) the Buckeye systems and service/Russ. A 75gpd Buckeye premium system is comparable in cost with a single 1 micron sediment filter, Matrixk 20,000 gallon 0.6 micron carbon block (the best), Filmtek membrane, and single DI stage at about $170. You can add a dual TDS meter if you want for $27.