I 100% agree with the other posters.. All of this ability to scale or really create and dial in your own recipes comes with knowing what your brewing gear has the ability to produce results wise and how it aligns accuracy-wise with any recipe building tool you may use.
Every tool(Beersmith, etc.) uses generic numbers to start you off with. Your mileage with your specific brewing equipment WILL vary..not may, but WILL.
Everyone's equipment behaves differently and even 100% duplicated systems behave differently in different environments and geos. Your tool is only as good as the numbers you can feed it related to your gears results.
Too many folks just blindly go with the tools recommendations and never go back to see how accurate they were hitting their numbers to adjust the tools to fit their equipment.
I cannot stress enough that you have to know your own equipment to be able to dial in any brewing tool for scaling a batch properly or your results will be hit or miss.
As for the OP's question, without knowing your equipment, any recommendation from me or anyone else here is just a guess and could end up being a good one or a bad one.
Learn your equipment and dial in your recipe tools around that information and scaling up or down (batch or ingredient-wise) will never be a problem again to get the desired result.