I ended up getting my WS1065 to work with non-P25 talkgroups, but for some reason it was really not liking P25 setups after the first time it was programmed correctly. It absolutely refused to pick up anything on P25 after I added more talkgroups, save for very, very rare and short transmissions. With non-P25 on the same radio networks, it catches everything.
These things are incredibly difficult to get working unless you have the settings just the way they want them. It amazes me that Whistler didn't include programming software when they directly advertise RadioReference as a programming resource in their manuals.