for smaller areas round the number plate as you said id recomend doing these by hand unless there is fairly easy access to the area with a machine and pad, if you really want to use a machine round these areas then the 75/80mm spot pads are better, the 135 menz pads will be fine but be carefull around edges because the pad doesnt protrude that far from a standard backing plate, the liquid shine pads have a recessed top so when the pad is put on the backing plate the edges of the pads have small ridge that protects the backing plate edge from coming into contact with the car . for roof/bonnet/door panels the menz pads are good.
if you do get them make sure you give them a good soak and squeeze out before you use them as they are very stiff before they get used.
Cheers Haze, I'd quite like to get the smaller ones so that I can get into the small areas like around the number plate. I was tempted by the liquid shine pads but for the price of the menzerna pads I've got to give them a go, havent I? 
they are ok but very stiff and quite small aswell and arent much bigger than the backing plates, im using liquid shine pads atm and they are very good imo and they've lasted quite well.