Whats really the max difference in mm you should really use wobble bolts???

The manufacture should tell you how much deflection they can cope with. if you use them, make sure the centre bore is correct

2mm for most wobble bolts.

So on a 4x100 Polo you'd be fine to fit 4x101.6 Mini wheels or 4x98 (Fiat?) wheels..

so asking 4.25mm is abit much then??

Yep

What wheels are they? Next size up is 4x108 which is like Ford and some French stuff..

I think there's a couple Rovers/MG's that are like 4/5x95. something..?

I believe they are mk1 escort wheels, look like alley cats. They are old school shizz and the pcd is 3.75" so dont really know anywhere you can get adapters for them?

I'm not sure dude, Google's just coming up with 4x108 for Mk1/2 Escort..

You sure they're 3.75"??

Definately 3.75", like i said i thought they were off a mk1 escort, may be off other car. But look like alleycats.

You need 4.75mm to make it 100mm. So you are only actually asking 2.375mm from each wobble bolt. I think you can probably just do it.