I have collected DVDs (prior to that VHS) of trumpet instructions for years. I have the two mentioned plus several others.
So far, I have not seen one that is really good when it comes to doing a serious job as "an instructor".
I'm sure most of the DVDs will be used only once or twice. This has mostly to do with the visual part of the medium (picture is the "winner" on DVD - sound is the "looser")
On the other hand I have some CDs that I use every day. The one I use most is this:
20 minute Warm-Up Routine
(I also alternate using the "15 Minute Warm-Up Routine")
Why?
Music is about sound. On DVD the picture take over - but on CD you use your ear and listen (nothing to watch).
It can be good to get Bert's DVD and see his instructions (how to hold, etc. etc.), but if you also get the "Warm-Up Routine", you will have something that will work for a much longer time.
Good luck!
Ole
P.S.
There is one DVD that I have used a lot. The Breathing Gym, by Patric Sheridan and Sam Pilafian:
The Breathing Gym