I tried it with a Franziskaner Weissbier and it was honestly pretty great. The beer isn't very assertive (and I used quite a bit more than just "a top up") but isn't overshadowed by the other ingredients either. Instead they rather serve to enhance the existing flavours in the beer. I was a bit concerned if the marmalade I had was too bitter but it worked just fine. It seems like it's pretty forgiving so you don't have to use your best bourbon, marmalade or Weissbier. Just use ingredients you like and it'll probably turn out great.

Is it an idea to swap bourbon for let's say a bold agricole rhum?

How much beer are you adding? I don't think I'm hitting the right proportions here.

Used one of my favourite witbiers - Gulpener Korenwolf. It's definitely more of an upgraded beer than a cocktail. If I came at this from the pov of a whiskey sour with wheat notes I would be disappointed; as a wheat beer with a nice orange and bourbon note? excellent.

IDK why you’d bother…too little beer and all you get is a typical bourbon/lemon cocktail taste…too much beer and you get neither beer as a flavour nor the bourbon. (Full disclosure: I used Erdinger Dunkel for my weissen beer.)