One of the most frustrating things I have found about monitoring TxWARN is that just about every object-based scanner (like the Uniden HP1/2, RS/Whistler PRO-668, and most others) has issues with the way they implement sites and layers, which results in the scanner constantly chasing control channels or scanning so many talkgroups that voice calls never get locked on.
This problem is exacerbated significantly by the fact that unless you are familiar with the way that TxWARN is organized into layers for different entities by phase 1 or 2 and split on a site by site basis, as well as the simulcasts carrying some but not all, et cetera - the default configuration that these types of scanners will produce results in a jumble of sites and talkgroups that will have you tearing your hair out trying to figure out why either it won't lock on a control channel, or if it does, it's silent 90% of the time.
Long story short, I have not ever been able to successfully monitor anything but simulcast talkgroups on the Montgomery County sites and only a few talkgroups on either of the Walker County sites unless I took the excruciating time to add a custom site definition with the appropriate control channels and talkgroups expected on that site.
It's only going to get more complex though, because once everyone in the region is on board, and phase 2 is fully online for all of the players involved, the simulcasting sites will become more and more important for those who want to monitor dispatch and other operations, because the simulcast sites are going to be the only ones that are phase 1 capable and thus accessible to non-associated entities like tow truck companies and the like.