Drum roll if you please......
A caveat to this recommendation - I ended up getting into quite a debate on this forum on the merits of a PRV (pressure release valve).
Firstly PRVs are a good idea to release the pressure when their is a blockage. But you may run into an issue with this fix if you dont address the design issues mentioned before.
If the CamVac is designed to pull a strong a vacuum, (on duel motor it provides a lot of suck) you may find the PRV is permanently open, that rather defeats the object of having two vacuum pumps, you might as well only have one on. Really you need to design the system to pull vac through the barrel in normal operation without any air leaking in other than from the shop tools (thicknesser etc). The PRV should only be activated in emergenncies - in the video, he probably had a tool with a very small pipe.
Its important to site the PRV close to the Vac pump ie the Camvac, as near to the vac as possible, alternatively on the barrel if that is close to the vac is a good option as there is plenty of space, but if you have a lot of pipe run after the barrel, you may be better to set-up the PRV at the end near the CamVac.. The reason being, is to avoid a blockage upstream of the PRV, (ie nearer the vac and after the PRV), as it wont be protecting that part of your system.
In your situation I'd go for a deeper barrel and reinforce if first, if you find your system is prone to blockages, add a PRV, your camvac will survive blockages for a short while. A PRV is a good safety and system protection, but makes sure its only being used to relieve blockages, or low air flow due to undersized or blocked tools, and not as a way of permanently reducing the suck of your Camvac.