OK cool, yeah the inside shot helps a bit.
With regard to earthing a new mains lead, I'd use the left hand side bolt holding the power transformer to the case. Remove both bolts and carefully move the transformer and PCB out the way so you can use a file/screwdriver/anything really, to expose some bare metal around the hole on the left hand side. You're trying to ensure you make a good electrical connection for the earth wire. From there you have a few options. The correct way to do it would be to use a solder lug like
this and a star washer.
You'd solder the earth wire to the lug, then assemble with star washer against the case, then tag, then transformer and tighten. I have seen people just make a loop out of the earth wire and use that instead of a lug, but thats a bit of a hack although, done right, it'll work just the same.
For the DC cables, I was expecting to see a center pole inside the socket (have a look at any of your stomp box's to see what I mean) which would indicated it was a typical 2.1mm (Sorry, I'm Australian, I'm not sure what that is in imperial) socket. In other words, the same socket as your stomp box.
Based on your measurements though, my next best guess is that they are 3.5mm (1/8") mono or stereo audio sockets. Mono would be sensible as you obviously only need 2 connections for DC, but the extra unused tag on the sockets might indicate they used stereo sockets, or they could just be mono sockets with two "hot" tags. It's not that important though.
If I'm right, you should be able to plug in any 3.5mm audio (1/8") plug and it'll fit. First thing that comes to mind are a set of headphones. My first caution though. I wouldn't just plug my headphones in to check the fit without either discharging the filter caps or snipping the red wire. There's a chance that even unplugged, the caps might hold a residual charge, and I'd not like to jam 9VDC into my sensitive headphones. I have dozens of audio connectors lying about so I'd actually just use one of those to test the fit.
So if all that works out, you'll need 4 of
these (or similar, you can go plastic for 1/4 of the cost, but the metal ones are of course more rugged) and then 4 of
these (again, plastic versions also fine if you feel metal is overkill for your application)
Lastly you'll need a length of dual core cable of almost any type. For 9VDC you can use ribbon type cable or coaxial type cable with no drama. You're limitation will be the thickness. You'll want something thats going to physically fit inside the plugs. Cramming some thick heavy duty cable in there will not help at all electronically at 9VDC <1A, so go for physical properties rather than electrical. My old pedal setup used 1/8" mic cable and my new one uses 2 core ribbon cable and there's no difference.
So I think that probably covers the "how-to" so it's time to get all serious.
I hold a restricted electrical certification, meaning I'm trained to replace mains cables (amongst other things). To do so without certification in Australia is illegal as there is the obvious risk of electrocution. Now I'm assuming there are similar regulations where you are, but in practice I'm doubting your going to sue yourself if you either injure or kill yourself doing this, and it's a very simple procedure so I'm comfortable advising you on how to do it, but keep in mind that I'm publicly stating that I accept no responsibility for you getting hurt if you mess it up. Check and double check the power side of this project before turning it on.
Sorry to be so blunt, but mix up your power wires doing this, forget to unplug the power lead before de-soldering the cable and you'll get electrocuted.
On a happier note, as you seem to have two of these babies, you could probably even make one of them negative ground (standard) and one positive ground for all your boo-tique fuzz's if you liked. I'd need a better shot of the bottom of the PCB to confirm, but I'd say it'd be dead simple. All depends what your pedal board looks like.
I have 3 positive ground fuzz's, all Germaniums but I run all of them on batteries only so for me, I'd leave both power supplies as negative ground, but it's all up to you
