I was thinking of using those
http://www.reichelt.de/Eingabetaster-Digitast-/DT-6-SW/3/index.html?&ACTION=3&LA=2&ARTICLE=7241&GROUPID=3280&artnr=DT+6+SW
instead of the Marquardt ...
they should fit if I pitch the second pair of solderinglegs ...
would make paneldrilling much easier ...