Just checked ebay prices on the DP34, and DPP44. You'd spend a little more money for the DPP44, but you save yourself the problem of running a 2nd coax to each receiver. With the DPP44, you would run one line to each receiver, then use the dpp seperator at the receiver. You would have one output off the DPP44 for future use (3 being used). A power inserter is required for the DPP44, so you need to find a place the inserter near an electrical outlet.
If you bought two DP34s (total 8 tuner outputs), you' have to run two lines from the switch to each receiver (since each receiver has two tuners), for a total of 6 coax runs. Two outputs would be available for future use. No power inserter is required for DP34s.
If it were me, I'd pony up the additional cash and go with the dpp44 install.