Nikon teleconverter (tc200, tc300)

I am using an old pre ai 1975 300mm 4.5 Nikkor that I ai'd for bird photography on a Nikon d200 digital body. I know this isn't the best set up out there but its what I was able to afford/ already had. I was given two Nikon tc200 teleconverters and have been using them but I know that with the 300mm and longer lenses you are supposed to use a tc300. I was wondering if anyone has used these and if it is really worth getting a tc300 teleconverter? or if the difference between the two isn't really that significant? I hope this is the right place to post since its old lenses but a digital body?