i don't use SMDs but i use 16x 1N4148 diodes that are quite small and 1/8 watt resistors some in very small packages.That is impressive! I can't quite tell from the pic but are you dealing with SMD stuff also? So tightly packed & so professional looking. May I ask what circuit /layout CAD you used?
A lot of work was done to pack everything around the controls potentiometers and switches.
That's why i choose a dual op-amp in a SIP8 package, the NJM4580 to be able to fit them in between.
Here's a picture of a pcb prior installing the ICs and controls.
SIP8 (single-in-Line package 8pins) one row of pins, 8pins.
the SW1 Mono/Stereo sw is in reality Quad/X-Stereo sw... a typo i made...