Big difference between the amount of fresh zest and dried. I find numbers saying fresh zest is 75-90% water so 40g would be equivalent to somewhere between 4 -10g of dry peel.
Also going to depend on how you want to use it, in Hoegaarden it and the coriander are a grace note, not dominating the flavour. Some brewers want Fanta like levels of Orange - meh personal taste.
I generally find with American recipes half the amount of any herb or spice will be at what for me is the high end, most commercially brewed European examples are very much at the other end.
Wheeler recommends 15g of Saaz and 3g each of bitter orange and coriander in the last 15 minutes of the boil in a 25L batch of Hoegaarden.
The Almanac recommends spices ( 83g Bitter Orange, 170g Coriander/hL) in a bag on a string for 60 minutes of the boil.
Pretty wild range from 0.2g/L to 0.83g/L, the latter probably being more American.
Mark