[Jukebox-list] what size needle to use?

[Rick Force]

Hi all,
I have a 1949/50 AMI C still on 78 rpm with the newer 45 conversion arm. I replaced the original Astatic 51 with a new style Astatic 51 with the flip over needle (LP on one side and 78 on the other). I believe this is 2 mil where as the original was 3 mil. I'm playing reproduction vinyl records (with a couple shellacs in the mix). Is 2 mil ok for this use (especially the vinyls) or should I use 1 (whats the difference between the 3 besides size)? Thank you, Rick.