Lar Dog,
There are a couple things to discuss.
1- Yes, many do run the 7.8 tubeless. For certain most of the ENVE Pros are. With a high end tire like a Schwalbe or Vittoria Tubeless tire the rolling efficiency is phenomenal and the likelihood of flatting is greatly reduced. The burrs you mentioned, if stuck in a tubeless tire, would be unlikely to cause a flat.
2- The 7.8 is optimized for use with tubeless setups. While it's completely ok to run a GP4000 w/ innertube, you have to absolutely follow a process for removal/installation.
First, tubeless rims have a bead lock. This locking feature is there to ensure an airtight seal and prevent tire from coming off the rim in the instance of a fast deflation. However, this same feature will also make it very near impossible to install and remove your tire if 100% of the tire bead is not off the shoulder and in the center channel of the rim.
When using inner tubes, you need to make sure that no part of the tube is pinched under/between tire and rim. If you do this, a flat repair takes no longer than any other rim.
Here is a video walking through tubeless set up. Just need to follow same steps but adding a tube is just another step.
https://vimeo.com/...oad-tubeless-install If this is still causing you a headache. Call customer service. 18014763363