Electronic – Looking for the solution for very close board interconnect using pin headers

Here's how it looks like

The small board with potentiometer is mounted above another board.

I used Connfly 1.27 pitch headers with 1.7 mm body height, cutting its body to approximately 1 mm.

But unfortunately I made a mistake in this design: 1 mm is too much, and boards must be closer than that. Both boards are having vias and pads, and while I cut all the through-hole pins (of potentiometer) so nothing protrudes, it is still bad idea to couple boards together for risk of shortage and capacitance, thus I need about 0.5 mm clearance. The headers are required for electrical connection, so they serve not only as mounting, but also for conducting.

Unfortunately I can not find any headers less than 1 mm height (and these are only on order). I am not sure I will be able to cut 1.7 mm thick header to 0.5 mm – it will simply broke during processing.

What would be a hack for this situation? What can I put between boards, preferably around the header pins, non-conducting and with least capacitance, to serve as a base for boards?

How would you approach this problem with minimal effort and in minimal time, given all the parts are already on the table?

Update: thank you very much for your answers. The plastic spacer solution would be great, except… my thought is that board will be subject to the physical force stress in its plane (when pressing and rotating the pot), and thus this stress will fully apply to the pins and then copper. Not sure how damaging it will be, but putting and leaving the spacer between boards where pins are located will make some relieve for these boadr-copper tensions. Would you agree to this point of view?

The material on hand from the defective power supply I was mentioning is ITWFormex, 0.45 mm thickness. It does not list the exact type of plastic, but looking to all the datasheets I see dielectric constant of no more than 2.22, therefore small spacer of 3 sq. mm with 0.45 mm thickness on the pins gives about 0.14 pF capacitance, which is tolerable within the design.