Merc Alloys - are these fitted right?

[skippymoss]

Hello.
Alright?
Just bought my first T25 (2.1DJ/Auto/Holdsworth pop - well happy)
It came with what seem to be Merc alloys as well as the original steelys
Had a good look around the Wiki and the forums but am still stuck (newbie syndrome? - don't worry 'll get the hang of it soon!)
The guy before me looks to have fitted alloys with no adaptations apart from longer studs and no changes to the tracking/ alignment.
The alloys are marked as follows; RG10 - KA41461 - ET23 - 7Jx15H2
The tyres are 205/60 R15 on the back and 195/60 R15 on the front
I think they're car tyres rather than van rated, therefore I'll need a full set of new boots fairly soon.
The spare is a standard steely with 185R14 tyre
Questions in my mind are;
1. What's the idea of running two different tyre sizes?
2. Would it be safe and how are you supposed to get home if you get a puncture?
3. How do I work out what size tyres to put on the alloys to make the spare a usable 'get you home' wheel in the case of a puncture?
4. What make/ type/ size of tyre would you recommend?
Appreciate any comments/ advice - Ta.

[Cruz]

The alloy tyres are -5.96% smaller on the rear and 4.13% smaller on the front than standard. Not sure what affect that would have on the spare

195/70/15 tyres would be exactly the same rolling radius as standard (these were used on factory fitted alloys)

There is a tyre calculator here (bottom of the page

http://www.brick-yard.co.uk/VehicleSpec ... ltwhls.htm" onclick="window.open(this.href);return false;