[waterfilters]

Since you are more concerned with small sediment and carbon filtration, I would recommend
Stage 1: DGD-7525-20 Water Filter and Pentek DGD752520 sediment filters for 20 inch Big Blue Whole House Housings
Stage 2: DGD-2501-20 Water Filter and Pentek DGD250120 Sediment Filter for 20 inch Big Blue Whole House Housings
Stage 3: CBC20-BB water filter and Pentek CBC-20BB carbon water filters 155312 for wholehouse water treatment

You will need a housing for each stage.
20 Inch Big Blue Whole House Water Filter Housing #20 from Ametek, USFilter, and Pentek
Here is a good bracket for the three hosuings: Three Big Blue Housing Mounting Bracket Pentek 144259 stainless steel for three Big Blue housings

You may want o-rings and a wrench available on the above housing page. Most people get a wrench at least.

If you want pressure gauges between stages, it definitely helps to know when to change the filters. This is what we have on our own system in our office between stages.
Liquatec Pressure Gauge PGB25100L measures pressure drop over water filters

If you'd like to keep it simple, you can use this system, which has the three housings connected to each other already.
Pentek BBFS-222 Big Blue Three Housing Water Treatment System with Mounting Bracket 160168

Thank you,
WaterFilters.NET