Was about to get a toy- then I did some research...

[NeoMorph]

I always have difficulty judging sizes from pictures. Usually have to get my callipers out.

[AndyUK]

I always have difficulty judging sizes from pictures. Usually have to get my callipers out.

They look like GX16?

The spindle will take a GX20.

I've been soldering lots of 7-pin GX16s and 4-pin GX20s this weekend.

Tip number 1: Get someone to help hold stuff. Failing that, grab a vise or something. And like ten of those helping hands things.
My technique (who knows if its good, but it seems to work). Tin the wires. Prep the pin with a decent amount of solder. Then flow it whilst simultaneously heating the wire, and bring the two together asap. Reflow once you're happy its in a good place to avoid a cold joint. Can be a real PITA when you're dealing with very short cable ends to keep it looking tidy.

Oh and DON'T forget to put everything on the right side of the damn panel. Spot the error below...

[Kitwn]

They look like GX16?

The spindle will take a GX20.

I've been soldering lots of 7-pin GX16s and 4-pin GX20s this weekend.

Tip number 1: Get someone to help hold stuff. Failing that, grab a vise or something. And like ten of those helping hands things.
My technique (who knows if its good, but it seems to work). Tin the wires. Prep the pin with a decent amount of solder. Then flow it whilst simultaneously heating the wire, and bring the two together asap. Reflow once you're happy its in a good place to avoid a cold joint. Can be a real PITA when you're dealing with very short cable ends to keep it looking tidy.

The vice is a must. If you put a socket (plug) in the vice and plug in the plug (socket) you're soldering then the socket (plug) will support the pins in place and help avoid distortion through overheating the plastic, though if you're as quick as you should be this won't be a problem. You're using the same method I do, just keep everything clean before tinning, don't twist the wires with sweaty fingers and clean the iron on a sponge between each application. Don't try using a gob of solder that's been sitting on the iron for a while. Sleeving over each pin will prevent shorts between pins or pins and the case.