While waiting for the PCB let´s use KiCad´s 3D view to show how the ZIF socket will look when mounted:

The ZIF socket is stacked in the DIL socket´s, i placed some resistors too close so on this version of the PCB its not possible to solder the ZIF socket directly... This will be fixed once i have build up the first amp and therefore discovered the other hidden bugs still inside...

It´s possible to use Dual or Single Op Amp´s, but dont use both at the same time, or maybe give that a try?

A 28 pin ZIF socket is used, that gives 1 row spacing between the Single and Dual Op Amp´s.

(the ZIF is not needed, inserting the Op Amp´s directly into the DIL sockets is ok. but it will not look as fancy...)