Yeah I don't make that many, I just like to make at least one so I know the design and layout is working as I caught myself out the once by making a silly mistake, If I need more then of the same PCB I get them made once I know it works.
I got the idea by stumbling across this web site and it got me thinking about it, I did a bit of research and thought why not give it ago. I only looked at that one because it uses a compressor as the vacuum I was going to use was not that power power full.
https://altrish.co.uk/2019/03/21/a-mini-vacuum-clamping-table-for-pcb-engraving/I had tried in the past the double sided tape but did not think it was that good or this may have been cased by the mdf spoil board I was using, may give it another go.
I use flatcam to create the gerber code and then autoleveller which I get descent results.
I have had success with double sided sticky tape and 2 part Cyanoacrylate glue. What kind of problem did you encounter?
In any case, MDF spoil boards, tape, and the copper board itself - *none* of them are flat (very likely not the vacuum widget either).
You must use software to build a height map so the Gcode gets small adjustments in Z as it moves along.
In my case I build maps no coarser than 5mm apart and sometimes as low as 3mm. It is an extra step up front that takes a couple minutes, but it produces fantastic results.
I'd like to hear more about your experiences as I am still new to this.