Good idea for an illustration. However, in my PF Core book, a Handy Haversack's central portion can hold 8 cubic feet, and each side pouch can hold 2 cubic feet. Cube root of 2 is about 1.25 feet, so those side pouches should be 1.25 feet on a side. And the cube root of 8 is 2, so the central one should be 2 feet on a side. Your diagrammed amounts are much smaller than these.
For regular Bags of Holding, I get the following- taking cube roots of each of the listed amounts in my PF Core:
Type I- 3.107 feet/side (30 cubic feet)
Type II- 4.121 feet/side (70 cubic feet)
Type III- 5.313 feet/side (150 cubic feet)
Type IV- 6.3 feet/side (really, 6.2996, but call that 6.3 for rounding error) (250 cubic feet)
A Portable Hole, of course, specifies how large it is on the inside, so that one's easy. Comes out to about 282 cubic feet in volume if we assume a perfect cylinder (3-foot radius, use pi-R-squared, multiply result by 10).