From what I’ve researched if you have at least an average draw length with 60lbs plus on draw weight a good rule of thumb is to shoot for around 280fps and build an arrow accordingly. If you are going with some heavy weight up front you will need to stiffen your spine. There are many calculators online for arrow speed and FOC, aswell all the arrow manufacturers now have some in-depth spine selectors.
Here is a speed calculator that has worked pretty accurately for me
https://www.omnicalculator.com/physics/arrow-speed