i wouldve been up for a few of these about a year back mate. i got up to about 40-50/180 of them signed then realised a few of them were dead so there was really no point in trying to get them all, but good luck with your seach
Im finding after a lot of research that most old players are ok about signing cards, I even got some back from the great Mal Meninga. Finding addresses to write to it tough, I sometimes get up to 6 RTS's before I get it right!