Determining the correct chain length (52/36 with 12/29 11S cassette combination) I have a Campagnolo Record groupset on my road bike where I want to replace the chain. My combination is 52/36 crankset with 12/29 (Chorus) cassette. I got a Campagnolo Record Chain 11-speed for this operation (this product).  

I'm on a DIY mentality recently and trying to follow instructions given from Campagnolo official YouTube channel videos, GCN Campy videos and the manual came in the box. However, I wasn't be able to adjust the height as it was defined on the 3 sources, where the distance between lower sprocket's chain and the lower chain should be between 8 to 15 mms (when the chain is on the bigger ring and the smallest on the cassette). For my instance, this distance is way wider, maybe 2 to 3 cms.  

To define better:


So I didn't see that as a big problem, guess the chain can make it with a couple of links missing, however when I put the chain on the small ring on the crankset, then the chain is too loose, it's simply swinging in the air.  

So my confusion here is that it is already a short chain when it's for the big ring but it's too long for the small. What way should I follow to determine the correct length in this case?

PS: The latest bikeshop shortened my old chain and since then, I wasn't be able to use the biggest cassette with the big chainring (I know I shouldn't, but even if I went to that gear accidentally, the RD would stuck and I had to take the rear wheel off to fix the problem) and also my FD wasn't working properly since the short chain was causing much tension and it wasn't be able to move the chain to bigger ring when say the grade is more than 0. So I can't take the old chain as a ref.
From the picture, it's clear you have a "short cage" rear derailleur. That could be a big contributor to the problem.

Rear derailleurs are rated for a certain maximum "capacity" that they can handle, which is the difference between the smallest total number of teeth and largest total. In your case, your system goes from 12+36=48 teeth to 29+52=81. This requires a capacity of 33T. Suppose your chain is almost snug when shifted into the 29 + 52 combination, so that the derailleur's tension pulley is almost horizontal, and then you shift into 12 + 36, the derailleur's tension pulley has to then pick up 33 teeth of slack.

A 33T range is about right at the edge of the capacity of a typical short cage derailleur, which is probably why you're having trouble setting things up to be okay at both extremes. It would be more comfortable with a middle cage length unit.