Calculation ibu

So acourding. My brewing software. The total ibu. Most the time around. 30 to 50% ok i know. The scale goes from 5 to 100. And the higher ibu. The more bitter. But what i dont understand. I do make a 15 gall brew. My ibu 39% is this ok for a 15 gall batch. Not calcutated. The dry hops. So i want to know. The max % to create a nice hoppy beer

Hop flavors / aromas can be visualized using a spider charts (for example: Hop Oils Calulator - Scott Janish).

Is that a bu/GU ratio? If so, it depends on the style of beer you’re doing. That ratio is helpful if you scale up. Let’s say you really like your 5% pale and want a bigger version… as you increase gravity, you increase IBUS to stay at the same ratio. Keeps things balanced.

Its more like. I am gonna brew a 16 gallon beer. A step up from. 5 gallon. This. Is a all grain beer so this means add more. Hops. As well. This is where i am confused. Dont want to over hop the wort

I use the JavaScript version of Morebeers IBU calculator and it allows you to plug in any size wort and OG. Simply plug in your new size and dial in to match your original.
Now Dry hopping is a bit of a guess , when I was doing NEDIPAs last summer, some approach it as if dry hopping does contribute some bitterness, about 10% versus zero which is more conventional …

What brewing software do you use? I don’t understand why you’re getting hops representation as a % rather than IBUs? If you scale a recipe up in volume you should still be shooting for the same IBUs to get a smilarly hopped beer. If you’re using Beersmith it’s very easy to scale beers up (or down) in volume. My 11 gallon batches have been almost identical to my 5.5 gallon batches.

The BU/GU ratio is helpful when you change or create a new recipe like @uberculture mentions but for scaling a recipe you’re happy with I’d ignore that and just shoot for the same IBU level as you increase volume.