You might want to try the fol. alternative multiple Antenna System that uses inexpensive Antennas, eliminating the cost and hassle of using a costly ROTATOR PLUS Antenna pretty much every time you change channels....and inability to perform rapid channel surfing....and many DTV's have a problem SAVING Channel Lists when rerunning SEARCH FOR CHANNELS at each of several directions. Fortunately, with NM in excess of 40 dB, there is plenty of excess signal strength available (to go through RF Combiners, etc), even in Attic Location:
FIRST of all you MIGHT want to determine if a simple Hi-VHF Dipole will reliably receive EITHER and preferably BOTH Ch8 and Ch10 at the same time from a particular Location in the Attic. You probably need to try several locations, incl. close to the EAST wall and also the WEST Wall. This test could be done using Rabbit-Ears (at about 14.5-in Extension for each Whisker).
If the Rabbit-Ears work for BOTH Ch8 and Ch10 at the same time, you could simply keep using them plus a UHF/VHF Combiner from A-D, R-S or "UVSJ" from Pico-Macom or Hollands. Or buy A-D VHF Antenna Kit [about $20 + s/h] which includes the UHF/VHF Combiner.
If you find you need More Gain for one or BOTH Ch8 and Ch10, you could instead buy TWO MCM/Stellar Labs 9-Element Yagis [about $25 + s/h] to point EAST and WEST respectively. You can use a standard RF Splitter/Combiner [about 4 dB Loss] prior to sending Hi-VHF Signals through UHF/VHF Combiner:
The most cost effective solution for UHF is to use a PAIR of the fol. 4-Bay Bowties [currently ON SALE for about $25 + s/h], pointed EAST and SOUTH, going through a standard RF Splitter/Combiner [about 4 dB Loss] prior to sending UHF Signals through UHF/VHF Combiner:
Xtreme Signal HDTV 4 Bay Bowtie Outdoor TV Antenna 50 Mile VHF/UHF (HDB4X) from Solid Signal
Although I haven't seen detailed SPECS, or accurate measurements from which to construct a 4nec2 Model, they PROBABLY are roughly equivalent to the CM4221HD, providing about 11-15 dBi Gain:
Since each UHF Antenna is pointed at nearly Right Angles to each other, the Multipath Crosstalk between UHF Antennas is very low. If one of the Hi-VHF Antennas results in excessive Multipath into the other Antenna, a Single Channel Combiner/Eliminator Filter MAY need to added....but bear in mind that 5th Gen (and later) ATSC Tuners built since about 2008 have MUCH BETTER tolerance to Multipath than earlier Tuners, so [Long Delay] Multipath Interference has become much less of a problem. [Short Delay Multipath, such as inside an Attic can still cause problems in some cases.]