tyres for my v50 outfit

Hi, can anyone give me any advice on what tyres to use on my v50 outfit, the tyres on the bike at the moment are standard motorbike tyres, the front being 3.00 x 18 and the rear 3.50 x 18 and depending on opinion I was thinking of changing them to a flatter sidecar type/style of tyre. Any help much appreciated as my sidecar knowledge is very limited. Cheers Chris.