@bkoster I just had my first successful Chromecast experience with Tablo, in more than 6 months.
What worked was: Tablo set to record at standard def and I used an android tablet.
Seems the app updates and Tablo firmware finally improved the Chromecast functionality but only for the setup they currently support… The android tablet app… Which is just a horrible device for casting. I mean, what is the point of 7 or 10 screen as a remote control. Stupid. Especially the Tablo interface when casting. Ridiculous.
So in the end… Casting from Tablo is still broke in my book. As casting from a phone device is the only thing that makes sense to me. Which by the way… Is still (really) broke for all android 4.2.1 and under devices.
Anyway, maybe you overlooked this setup and may find it acceptable.