Sorry if I missed something along the way, what is the Age condition of seeds?, conditions for storing?, sterile environment? mishandling?. I've been using my oma's ideas for years.
Make sure seeds stored in cool dry place, handle them as little as possible (oils in our skin contain massive amounts of salt and chems. comparitively.) Keep clean working area, while germing, dont trip, moist paper towel in quarters above fridge or in cabinet, just give them 2 days and keep moist, immed. plant the sprouts in the darkest possible environment, hydrodome works well for me, use tweezers if needed. Keep them in the dark until first signs of cots. 80-90 success
I am not an expert, but the whole idea of peeling back and damaging the seed first, well think about it if it was your kid. These are plants, and they have been living for millions of years without our help, If its not the seeds, it the handling and conditions. Keep it simple... just saying