How to make strong concrete piers for a cabin?

My new cabin (on Canada's east coast) has to be built on piers, due to planning/zoning requirements. 28'x28' I'm doing 20 concrete piers, five rows of four, which allows for a big porch off the front.

Any advice on making my piers really strong?

Here's the plan so far, but I am open to feedback! - the build pad has already been compacted, with crushed rock last summer - hammering in 4 rebar per pier into each place - making my forms 24" x24" x 24" - getting the concrete delivered and will have it piped in.

The height is to give a crawl space under for kayaks, lumber and to winterize all the plumbing.

Still undecided on having saddles. Mobile home owners seem to unanimously adhere to the principle that if your blocks settle, you want to be able to shim spacers in there.

Q1 - Would anyone opt for concrete blocks instead of poured? Q2 - Has anyone done this before and recommend any changes to my plan?