boats

I have a 1989 FJ62 Land Cruiser that still runs on the factory fitted size 7.50 R16, however, I'm experiencing alot of punctures on long distance trips. Off-road and on-road alike. My question is this, should I fit bigger tyres on the vehicle and if so, what size tyres should I get? Also, if I do put bigger tyres on the vehicle, would a bigger spare wheel fit underneath the vehicle, or should I also fit a rear wheel carrier?