1H, 1S, 1 vol, 2 tone, 5 way switch - questions

I've never really understood all the science behind the wiring, pot resistances, tone caps and how/why different components have different effects/sounds. I usually just find compatible wiring diagrams for what I'm putting together and go with that without really understanding what I was doing. However, what I'm putting together on my current build is a bit different from common builds and the corresponding wiring diagrams I've found don't answer a couple of questions I have.

The build in question involves 1x humbucker and 1x single coil. It's in an ST kit, so the standard pick guard has provision for 3x pots - therefore, I'm opting for 1x vol, and a tone pot for each pickup. There's a 5-way switch and it will be wired for:
1. Bridge humbucker
2. Bridge north
3. Bridge north + neck single coil
4. Bridge humbucker + neck single coil
5. Neck single coil.

Here's the proposed wiring diagram:

Attachment 44894

The questions I have are regarding the pot types I should use. The diagram doesn't specify and I can't find a definitive answer. I'm going with A pots for all three, but I'm stuck on the 500k v 250k part. From what I understand, 500k is usually used for humbuckers and 250k for single coil (although not a strict rule, it's the norm). What I don't know is if I should follow this rule here and get a 500k for the bridge tone and a 250k for the neck tone or if it's not advisable to mix them in this configuration, especially since two of the switch positions use both pickups. If I should be sticking with the same values for both, I'll be leaning towards 500k as I'll probably be playing with the bridge 80% of the time.
A secondary question is regarding the volume pot. Is there any difference between using a 250k and a 500k for the volume?

I'd really like to be able to understand the mechanics of all this wiring of pickups, pots, switches etc so I could look at these wiring diagrams and understand the purpose of each connection.

In answer to the question about the pot values, in general the lower the resistance the more treble gets filtered out. 250K pots are usually recommended for single coils because they produce a lot so much high end treble that it can be harsh. 500K are usually recommended with humbuckers because they tend to already be filtering out some of the highs, so most folks want to allow as much treble as possible to pass through. I don't think there is any rule that says you can't mix and match pot values. Danoelectros do it all the time. On the other hand you could use 500K pots in all three positions, and if the single coil seems a little harsh you can just roll back the tone control a little.

One thing to consider is that humbuckers tend to be more powerful than single coils. Not a big deal when you are running the pups by themselves, but in the middle position, the single coil may not be able to keep up. Something you might consider is two volumes and one tone. That would allow you to compensate for more powerful bridge pickup if it turns out to be unbalanced.

Another thing that occurs to me is that you might want different cap values (something darker...higher cap value) for the single coil than for the humbucker if you do go with the two tone controls. If you use a .22 with the humbucker, for example the same value may not get you much tone roll-off with the single coil. You might want something like a .47 The wiring diagram in your pic only uses one cap, but you can use a different cap for each tone control if you want to.