I would place the UHF antenna (DB8E) at the top of the mast and the VHF antenna below it so that there is 3' to 4' of space between the two antennas. This means that a 5' Mast will be too short. 10' TV antenna mast has become hard to find so I have switched to using 1 3/8" diameter chain-link fence 'top rail' or 1" IMC electrical conduit. Both are in stock at the local big box home center.
If no preamplifier is used, or if you use a preamplifier with one input, you'll need a UHF/VHF combiner. Examples:
http://www.amazon.com/Antennas-Direc.../dp/B008PBTPN4 &
http://www.radioshack.com/vhf-uhf-go...l#.VMGa1zVVKlM The UHF/VHF combiner is a passive filter network that allows you to connect one UHF antenna and one VHF antenna to a common coax down-lead. If you use a preamplifier that is equipped with separate inputs for UHF and VHF antennas, you will not need the stand alone UHF/VHF combiner. The RCA TVPRAMP1R is a dual input preamp. It's my understanding that Antennas Direct has a new preamplifier that will be hitting the market soon, the advance information I have so far is that it is a single input design and it can tolerate a mix of strong and weak signal inputs.
But as I mentioned earlier, I would test reception of each antenna (using the procedure I linked to) before committing to the purchase of a preamp or combiner. Your TVFR suggests that you may be able to run with no amplification, but you're at the threshold. It's going to depend on how much loss there is in your cabling/splitting.