I plan on using two HW-150s in series, using the RF out (with "Loop through" Modulation setting) of the first unit sending the antenna signal to the second unit. (So no splitter necessary for this.) That way I can record back-to-back TV programs (even on different channels), without losing any of the second program's recording. (Which can happen with just one unit when it's switching to recording mode for the second program.) With two units, both units can be programmed to record their shows a bit early, and end a bit late, without a problem. So I will basically have a two tuner DVR setup (like I had with the cable company I cut the cord from). Since my TV has multiple Component and HDMI inputs, I won't even have to move cables to watch either recording; I will just need to switch inputs on the TV.
Note: In the past I've repeated a suggestion which I read somewhere, but which I recently discovered will not usually work: using polarized filters over the remote's IR LED and each box's IR sensor, and rotating the remote to control one unit or the other. The problem is most polarized filters work only over the visible frequency spectrum ant not at IR (not even near IR) frequencies. There are near-IR polarized filters (for photographers), but they are very expensive.
You need a KLUGE!