[autoavia]

Silicon tyres put a film of silicon onto the track and will ruin the grip for urethane and rubber tyres so if you buy silicons for this car you are going o need to buy them for any others that you run on the same track. If your track tends to get dirty you will also find that silicons will pick up all the dirt from the track very quickly and then lose grip. 
In the 60's if you turned up, at a commercial raceway in the UK with silicon tyres you wouldn't be allowed to run the car unless you changed them for something else. They allowed silicon tyres at the annual vintage meeting in Bordeaux a couple of years and have loads of complaints from racers who found that if they ran on a lane immediately after someone who was running silicons there was no grip. They now only allow them in the "thingies" class and run that at the end of the meeting.

[Charlie]

I think the message I am getting is just to run a stock motor and sort the existing tyres, they are new so a bit of a scuff up, thanks everyone for sensible comments

[Kevan]

Glue & true the stock tyres first, then you can 'treat' them with 3 in 1 oil very thinly smeared round the tread...leave for at least 3 hours to let the oil soften the outer layer of rubber.

Olbas Oil or Tea Tree Oil work even faster (honestly it works, it's the Eucalyptus oil) but the effect isn't as lasting as 3 in 1 oil.

After market tyres make a bigger improvement, NSR Supergrips or Thunderslot standard tyres are two good examples.

[Charlie]

Does glueing tyres make them difficult to get off at a later date ?

[Kevan]

Not particularly.  I'd rather have tyres that didn't try to roll off the wheel in corners and deal with removing the old tyres later on than have the convenience of not glued but the rear end hopping and jumping about as the tyres roll over.

Once the old tyres are ripped off cleaning up with a file whilst the rear wheels are spinning gets them ready for a new pair.

[Charlie]

Ok, oiled tyres with 3 in one, how often should I re do them ?  And how can I find correct tyre size for a wheel,  it’s 15.8 x 8.2.  Thanks

[Kevan]

Ok, oiled tyres with 3 in one, how often should I re do them ?  

With NSR tyres (not the Extremes, don't get oil near those...in fact don't buy those, they ball-up just looking at them) you can get away with once per day for a week then they'll be as good as they get.

And how can I find correct tyre size for a wheel,  it’s 15.8 x 8.2.  Thanks

If I have a wheel that size I'd fit my favourite tyres that will fit, so 9mm wide and 20mm diameter.  Rubber stretches, don't get hung up on getting tyre sizes spot-on (unless you're going down the silicone tyres route), I recently stretched a pair of Thunderslot tyres 10.8x19mm over a pair of 17mm dia wheels.