ok, thank everyone...

I did have a more narrow campy chain on previously, but changed it out to the SRAM due to it being so narrow it got stuck between the two front rings... so that was solved, but the skipping still persisted.

the cogs were looking pretty new when I first mounted it,

Now about the chain tension... when the chain is on the 13t cog and the 39t ring it does have a little bit of slack (by the touch it feels a bit loose)... but if I get them on the 18t and 52t the rear derailleur is nearly straight, straight being where the chain is on a straight line through the jocky wheels in appose to "s" curving through. So I was afraid if I shortened it any further it might distress the rear mech?

would a pic of each position help?