How much percentage of honey can be add in to the dough ?

A quick search shows this one has 8.4%.

Honey-Oat Pain de Mie has 18%.

I call it the Trinity. It started when a frequent poster Danni was putting yogurt in almost all of her bakes. Sometimes honey as well  as  olive oil. I decided to give it a try and put all three. It now is a feature in all of my breads. I simply add 20-35 grams of each for every 1000g of combined flour. It doesn't seem to make any difference except the more honey the easier it is to get a rich brown crust and the olive oil and yogurt ( or buttermilk) make the crumb very flavorful and amazingly tender. There are no drawbacks at all . I subtract the 60-105g from the liquid called for in the bread formula.All three components are added at the initial mix so yes they autolyse altogether.  I don't change anything else at all in the way I bake or let the dough mature or retard. Give it a try with the smaller amount of 20g of each honey, olive oil and yogurt or buttermilk and see what I mean .  A number of TFLers are using it and have all posted success . c

Panettone is an example of a sourdough bread with the highest amount of sugar in it. Up to 700g per 1 kg flour in panettone (70%). Honey is 82% sugar and 18g water. So, you could use even more honey than pure sugar if you wish so. 

8% is perfectly safe. 

It depends on the recipe, but usually no more than 2-3 tablespoons of honey per cup of flour.