The original Midget came with a set of 13 x 4.5 Rostyle wheels. My car came with a set of 13 x 5 KN Minator alloy wheels. I renovated these and fitted them with a set of 155 80 R13 tyres. I kept the front tyres it came with on the front, which were Autogrip, and replaced the winter tyres it had on the back with Michelin Energy E3Bs. These were very good, a lot better than the Autogrip tyres on the front! They looked very narrow though, and once they were worn out the whole car got a set of 175 70 R13 Continental EcoContact 3. These provided much more grip, without too much impact on ride or handling. These required a bit of a spacer on the back to stop the sidewalls contacting on the springs, and spacers on the front to balance it out, with longer studs to suit (get Grayston ones from Minispares, available in a variety of lengths)
The change to very big brakes heralded a set of 14 x 6 Minilites, genuine ones, from eBay, never fitted, for a lot less than the RRP! These are shod with a set of 185 60 R14 Uniroyal RainExpert tyres, which are brilliant. They are not very good on track though, and I melted them at Croft, so now I have a spare set of wheels (14 x 5.5) with 185 60 R14 Nangkang NS2-R track day tyres on, which are a lot more stable than the Uniroyals on the track, but a lot worse on the road, especially in the cold and damp conditions often experienced.
The 185 tyres would be too wide for a standard car, but they work OK. I may well change to 175 next time.