Watson, I don’t think anyone explicitly answered your question, so I will make a stab at it.
Cutting 4 7/8” squares and then either 1) cutting diagonally or 2) marking the diagonal line and sewing 1/4” on either side then cutting on the diagonal (same process in a different order) will put into your hand a HST measuring 4 1/2” unfinished size that will measure 4” when sewn into the quilt. Unfinished size means the size of the unit before being sewn into the quilt and finished size is the size of the unit after sewn into the squilt.
You want to use the 4 at a time method, here are your sizes for beginning squares:
- larger squares start with 7” squares and trim the units to 4.5”
- smaller squares start with 4.25” squares and trim the units to 2.5”
All of the outside edges will be on the bias, which is why so many people said they didn’t like this method.
If you want to use the 8 at a time method:
- larger squares start with 9.75” squares and trim the units to 4.5”
- smaller squares start with 6.75” squares and trim the units to 2.5”
Advantage is that the outer edges are on the straight grain of the fabric which minimizes stretch. Disadvantages are you need to mark the diagonals and you get 8 HST exactly alike, which might not work with the pattern you are making.