Now you've got me motivated to try Spinach transplants in DE.
I've always direct seeded spinach, sometimes with mixed results because if the temps get hot early in spring it wants to bolt or if their is too much rain the seedlings get drowned. I know what you mean about the difficult germination problem.
I'd like to get some transplants in the ground and containers this fall to overwinter for a early spring crop. The best spinach I've ever grown was started in fall and overwintered.