Tom Turkington from Tempest responded:
We have seen this work well from a Tempest perspective by simply operating both systems in the full band mode and getting good physical separation on base antennas. There have been some reports, though, of the DX users experiencing clicks. The Tempest users seem to be fine.
You could do what you said about splitting the band, but you limit the number of Tempest bases you can use in that area and you reduce the amount of interference rejection that would normally come via hopping over the entire band.
Let me know if you want to talk about it further.
CoachComm / Tempest Wireless