Modular Synth Panels

Hi,

I need your advice on designing Eurorack front panels. 

Some manufacturers use slotted panel mounting holes (Cwejman, Metasonix), whereas others use round ones (Doepfer, Analog Solutions, Harvestman) as per the Doepfer specifications http://www.doepfer.de/a100_man/a100m_e.htm.

What are your experiences? Are you occasionally having troubles fitting modules with precise holes?

I am planning some very narrow modules (4HP) and slotted holes would further reduce the limited amount of space available for labels. Also, I'm using 2.5mm screws...