Questions on drive size/types for new build?

I am starting to gather hardware for a build to replace my aging Late 2009 27" iMac. It has a 1TB internal drive that is used as follows: 900GB OSX Sierra partition 200GB iTunes library 190GB iPhoto library 131GB apps folder-may be able to reduce some, but already have infrequently used compressed 100 GB bootcamp partition (windows 10) this will be on a separate drive on the new build-not an issue.

I know operating systems on separate SSDs. Windows mostly for gaming so 250GB should be enough 250GB (enough?)SSD for OS X, 1TB 7200rpm drive for iTunes, iPhoto, and Documents. Does the apps folder need to be stored on SSD or can it be on spinning drive? Does having it on spinning drive hurt performance much? Would it help for the spinning drive to be a hybrid drive like Seagates FireCuda?