if i wanted to put a turbo in my 1200 datto would it be pointless ?? if not what size should i use

It would only be pointless if it's a poorly designed set up that causes more problems than it solves.
Turbo size depends on what motor you are planning on building.
If you do a search on this site you will find pages of information on turbocharging an A series, CA18DET conversions etc.
Topgear recently had a lot of success in turbocharging an A series motor so have a look for his posts in particular.
Regards Matty

Davos, do it man, you won't regret it! Done properly, they are very streetable and lots of low tech fun! If you want the easiest way a suck thru is the best. Standard fuel pump on mine (A14) and makes 90 rwkw. If you run a blow thru set up, you can intercool it, but will need high pressure pumps, similar to efi.