If I am reading this correctly you are asking for the cutting measurements for both the HSTs in the Pinwheel and the squares in a Four Patch? If so - here it goes .... if not .... sorry
Each pinwheel is made from four HSTs. So each HST will finish up to be 4 1/8 square if the entire square is to finish up at 8 1/4.
Yes, for the HSTs in the Pinwheel , this is where that pesky 7/8" comes in to play. Your squares should be cut at 5" square. (I am of the school - better to be too big and trim - so I would probably cut them 5.25 then square up after construction).
If you are doing just a plain 4 Patch - the finished subsquares again would finish at 4 1/8" square. To that you would add 1/2" - so here your squares would be cut 4 5/8". Again I like to trim square, so I would probably cut mine at 4 3/4".