I tried the vacuum with the DVR and it did not work well at all, I could not even sand, let alone turn the bottom of the bowl.
Thus, I'm looking for a vacuum pump.
I was surprised at how well the DVR vac hookup did work.... so let's review what I did, and maybe can find why it didn't work for you. If you think this would be better as a separate thread, please use your Moderator skills to do it.
First, vacuum chucking won't work with very small pieces. If you are turning a piece with only 1 square inch outside surface, and had a perfect vacuum (you won't) it would only have 15 pounds pressure holding it on the face plate. On the other hand a 6 inch diameter plate (so I can use 2D math rather than 3D) would have about 28 square inches of surface, which in theory could have well over 400 pounds of force. Even at 50% effective vacuum, that 200 pounds is still ample for gentle cuts. If you have a 6 inch diameter bowl rather than a shallow plate, I think you will have the same force onto the faceplate - I bet the extra surface area will probably just contribute to forces trying to collapse the bowl sideways (but it has been a long time since those engineering courses).
As you know, the DVR vacuum adapater is just a bearing that fits in the headstock (held by a setscrew), and a short pipe that comes out of the bearing. That pipe has a hole in the side to allow airflow to your shop vac so that the vac doesn't burn up. A piece of masking tape fixed that hole... I have enough leakage in the hoses of my old vac, and my new vac has a separate cooling fan.
I installed a vacuum connector (like a tire air connector... air pressure hose connectors do not work for vacuum) in that pipe (to use with my vacuum pump), and also turned a piece of soft wood that fit over the pipe, the outside has a slight taper over which I can slip on my shop vac hose. Thus I have fairly good connections to either shop vac or vacuum pump.
For the vacuum chuck I cut a piece of 3/4 inch plywood about 10-12 inches in diameter and attached it to the face plate. I drilled a hole in the center, then turned the edge so that it would be balanced on the lathe. I found some "no slip" kitchen shelf lining that appeared to have closed pores (think a 1/8 inch thick sponge pad that was airtight), and cut a circle to fit on the plywood faceplate. At first I used some two face tape to hold it, then went to spray adhesive. Still need to refine the glue process, but once I am spinning, no problem.
Before the first use, I touched the pad with a pen, while turning slowly, so I have a set of concentric circles to help center the work.
I have used two techniques to mount the work. With the lathe stopped, I hold the work on the face plate, carefully centered on the circles, then attach the vacuum and go. Or I leave the vacuum loosely attached, and slide the work around until it is centered with the lathe turning slowly - when it is centered, push the vac hose on fully. Don't try to slide the work with full vacuum... it tears up the pad.
I doubt if even a fancy vacuum chuck would be as strong as a four jaw, but I have had no trouble taking gentle cuts and sanding. But the amazing thing to me is that the shop vac holds as well as the vacuum pump. Since I have a continuous duty vacuum pump, all the air moved to make the vacuum goes through the pump immediately, so it is vulnerable to sawdust contamination (dust plugs the protective filter). Therefore I usually use the shop vac on the lathe.