Outer Limits 4x4 Board

So I've been looking into fiiting power windows for a while, and I figured whilst I have the dash out, I'd run some wires. So...

a. What sort of amps are they likely to draw and what size wire should I run? 4mm-15A? Bigger-More?

b. I was going to run 1 relay so that the whole lot is activated by the accessories switch (to prevent someone opening the window with a stick), then (87) to driver window switch (and passenger overide). Then (87A) to passenger window switch. However this would mean that the PW motor is drawing it's power through the up/down switch intstead of straight off the relay.
So should I run additional relays for up and down so that the power going to the motor isn't drawn through the switch?

Make sense? No?

Thanks for all the replies!

So the motors I've picked up appear to have 2x 4mm wires coming out of them. So that's what I'll use.

And I was a bit wrong with my wiring. It'll be done like this: POWER WINDOW WIRING DIAGRAM
The wire from (87) will come straight off the battery and the power to (85) off the accessories.

On a side note, In a standard setup ie: driving lights, I thought (87) and (87a) were both linked when power was given to (30). So power to (30) and (87) to 1 light and (87a) to the other. No?

87 is normally open, and 87a is normally closed outputs.

some relays come with two 87 pins. so you can do as you describe. these are normally called 5 pin NO (normally open) relays or headlight relays.

also, most factory electric windows pass the current directly through the switches, no relays.

if you get DPDT switches capable of handling the current then theres no reason you cant just use them without the relays.

Yeah I since realised I had always used what is called a 'standard' relay (4 or 5 pin (the 5 pin having an additional 87)) and I needed a 'changeover' relay (5 pin (1x87 and 1x87a)).

I needed to run them through a relay as I am having it isolated by the accessories switch. Otherwise any Tom Dick or Harry could open my window with a stick or coathanger and I did not want this. It's literally a 2min job to change this if it gives me the shits.
So I needed at least 1.
But as it turns out, the motors only have 2 wires and operate on 'reversed polarity'. So connecting it one way will make it go up. The other way will make it go down. So I need to solenoids for each window. I have 2 windows, so need 4 all up.
That link explains it alot better. So I don't think I could get away without using ANY relays.

I followed that diagram and it works great. All I need now is some rocker switches and I will finish the job.
On the passenger side, I ran an additional wire out of both (86) terminals and ran this to the drivers door so that I can open the passenger window from the drivers side (Part of the reason I'm doing this is my car has no air con (yet) and I am sick of leaning over the other side and fiddling with the winder).

I overkilled on the wiring (didn't realise until I'd done it).
I ran 15A for constant power. 10mm for the accessories power. 15A to the motor.
And 15A to the switches. This was the overkill as all the switch is doing is operating the relay, so doesn't need to be 15A. Which would have made it easier to fit through the passenger door.

I am not an auto electrician however so please correct me if I am wrong.
I am mainly posting all this for future referance.

you could have used 1 relay switched from accessories to feed all your window switches.

and then used your momentary rockers to handle the current (which they more than likely will be able to handle).

but i would have done it like you have, with 2 relays per motor, as its neater and means your switches wont ever wear out, like most factory window switches do as they are handling the 10amps etc.