The DB8e is a very capable UHF only antenna. You also have High-VHF signals present, and may need to add either an Antennacraft Y5713 or the larger Y10713. The UHF and VHF signals can be combined into a single cable using an Antenna's Direct EU385CF UHF/VHF Antenna Combiner or Radio Shack # 15-2586.
The CM-3412 would easily drive two 4-way splitters. The ideal location for any amplifier is near antenna, on the output of the UHF/VHF combiner. The CM-341X type amplifiers cam be powered remotely, either by way of a separate cox run or by sending power backward, up the coax with the addition of a PCT-MPI-1G Remote Power Inserter.
http://www.amazon.com/PCT-Inserter-M.../dp/B005Y12UH6 Generally, you would need to place the power inserter between the amplifier and splitter, unless you use a power passing splitter. Example:
http://www.antennasdirect.com/store/splitters.html