Ok been reading the forum and other sources of information with regards to jailbreaking an iphone 3GS. From what I have read on hear jailbreaking an iphone 3GS and updating to ipad baseband prior to week 35 of last year is ok and can be done with Redsn0w. I fully understand the implications of updating to this baseband.

Having recently downloaded sn0wbreeze 2.9 I looked at installing the ipad baseband via this method and that warns that if you install the ipad baseband on to a device after week 28 then you will brick it.

Further reading has led me to a page that states that it is only the 8 gb week 28 iphones that would brick so would sn0wbreeze work on a 3GS 16gb past week 28 but prior to 35 or would I just as well use redsn0w?

I didn't know that, but quickly searching around, it seems you're correct. For the 8GB 3GS, they have confirmed new models with the new baseband as of week 28 of 2011. For the 16/32GB versions however, none have been found prior to week 35.