Would you guys recommend a 4/5/6 point harness for racing and are they all a standard size?

If you are going 'circuit racing' your belts will need to be FIA homologated harnesses (and in date).

For speed events (hillclimb & sprint) the belts do not need to be FIA.

If you have a reclined driving position you would need crutch straps (5 or 6 point) harnesses.

If your car would run in Sports Libre category in speed events then 5 or 6 point are mandatory.

If you intend using a Hans device you should consider belts specifically designed for use with the Hans device.

No need for HANS but I will need FIA approved. I presume 5 point is a recipe for pain the in the nether regions?

Better than the pain of submaring the seatbelt and falling out the car.

So 6 point it is then..