Eric,
The switch pots are a great idea, though high-quality ones seem rare.
They’re often audio taper too and we both know that won’t work.
You can also use one set of existing switch contacts on something like the ext in switch or some other switch with double contacts. (very early Minis didn’t come with DPDT switches though.)
Then there’s no holes drilled, but some switch not often used can play double-duty. I’ve done that on Minis I’ve modded with suboctaves or ring modulators, but so far not with sync.
Some people have rewired one of their accessory Cinch Jones connectors for external control. Few people use 'em, especially both at the same time.
The plugs are easy to find and the look of the mini doesn’t change. 
Fwiw, the secret to not bending the removed bussbars is to never push them or at least not from more than about 4" away.
When I polish the bars, I pull them back through the guides. Pushing can bend them and thus mess up timing badly, especially on Minimoogs. It helps to slightly file the end of the bar sometimes too.
When pulling them through a cloth, don’t grip them tightly either or they’ll bend.
Be careful on the Moogs towards the late 70’s too.
Gold prices went up then and the plating was sometimes thinner.
The bars themselves are copper, which is a great conductor but tarnishes easily. Remove too much plating and they’ll work great… at first. 
Btw, the more Minimoogs I worked on, the less I thought they were easy. 
I learned more and more differences between the various production revs and why the changes were made. I realized which parts aged badly and which ones didn’t.
So encountering an early Mini might not affect someone else in the same way it does me.
I never noticed all the differences before.
Now I think of why Moog implemented a certain change and want to do that too.
Also be aware there are a few errors in the schematics and many changes that weren’t documented.
For example, later Minis had 3 capacitors in their power supply, instead of 2.
This alone can explain some of the differences between very early Minis and later ones: there’s a big difference between having two 35 year old 500uf caps and having three 20 year old 1000uf ones.
I tend to add the third cap, whether it came with one or not.
(the values changed through the years too.)
Also, most Minis exhibit an attack glitch on their filter env.
It can overshoot or undershoot the sustain level.
Try yours (full resonance helps.)
I like to make that glitch disappear nowadays, but I never noticed it before.
Now it bugs me..