You tell us you want to use a 20 or 30 dB amplifier for each feed coming from the cable box to feed your tv's. Do you know, the distribution amplifier from the cable company feeding your entire street has an output of about 36 or 38 dBmv on channel 3 and about 45 or 48 dBmV for the higher channels.
If your signal at the input of your 20 dB amplifier is 5 dB on channel 3, you will have 25 dB, it's very high to feed a 4-way or 8-way splitter. You are not feeding a street.
The best thing to do, is to bring all the cables to one location and let the cable guy installing what he need to install. All the splitters, amplifiers installed by cable companies are SCTE certified and are build by the same manufacturers building distribution amplifiers, line splitters, connectors for the cable networks.
You asked to give you advices, it is what we do...