Okay, there is a lot of info with the vaccine and if you go through Jeffers, ask to speak with J. R., just the letters and if he's available that man can tell you everything you'll need to know. there are also quite a few things here on BYC that can give you the info you want. This blood test is done with specialized equipment and is pretty much fool proof from everything I ha used it yet as I found out about it after the worst of miney outbreak had already passed and a second necropsy showed Marek's. The first one did not, even though I 'know' the bird did in fact have Marek's. I think this pretty much answers my opinion on necropsy or this blood test. As for different sized needles and different dosage, call and ask to speak with JR. He can guide you to what you need.