AccentOnHakes,
I think we read the same book, Storey's Guide to Raising Chickens, because I was concerned with the same thing. I fed Starter, 22% protein, to mine until they were about eight weeks old, then began to give them a little bit of homemade scratch in the form of an oat, wheat mixture in the mornings and night. I still kept the starter out for them, but because they ate the scratch, they filled up a bit on that and didn't eat so much of the higher protein. My intent was the same as yours.
As they got older, I gave them a bit more scratch, this time with some BOSS (Black Oil Sunflower Seeds) mixed in, mornings and night again but switched them over to Purina Flock Raiser and free choice oyster shell when they were around 18 weeks old. I continued the scratch, maxing out at slightly over one cup of scratch between six standard pullets.
The first egg came from a bird that was 26 weeks old and the last was somewhere around 34 weeks old. They have all been nice and hard shelled, no problems and the girls are very healthy.
Having said that, they are now only 10 months old and some of the laying problems you described often start as they get older, although I've read of egg-bound birds under one year old.
I'm happy with what I did, the girls are healthy, and I'll just wait and see what happens. They now get about one cup of the scratch just before bedtime to fill their crops.
Mary