Tiger I early production were they Panzer grey or Panzer green? What would be a good acrylic for Panzer green?

All German vehicles until mid-1943 were Panzer Grey (except for those in North Africa). So your Tiger should be overall Grey as long as it is before the above date. Occasionally they were oversprayed with green, or white camo, and older vehicles during the Battle of Kursk could be seen with a green, sand, or brown overspray on the basic grey. Some early Tigers in North Africa were done in a controversial shade of green (no one can quite agree on exactly what shade it was!). Hope this helps.

Opening a can of worms here......

Green is very, very, very unlikely. Some Tigers in Tunisia were painted green (or even OD) according to legend, but the facts behind the legend have not been tracked down.

So Dunkelgrau (dark grey) for Europe and this camouflage for Tunisia

http://www.tiger-tank.com/secure/journal27.htm