What fan to use with smaller radiator

[Rossi.D.25]

I've a set of throttle bodies fitted, I've got a smaller radiator I just need to know what fan to go for, Where to place it, ive seen people putting them on the front of the radiator, also can buy a fan to suck or a fan to blow, which one to go for??

 

[bloke]

early scirrocco rad and you can fit two 13" (possibly 12" but can't remember) fans on the back.

will be fine with just one if you want though, for competition bigger power stuff i throw two on but never had any issues with overheating with one.