My birds do not follow Henderson's Chart. My Buff Orps are almost as good as my BRs, even at three years old. Much depends on your maintenance and nutrition of the birds, IMO. I agree with what Dipsy said about the BRs.
If you want a real laying flock, one that does not go broody, I still say BRs. Now, I know many love sexlinks, but I just don't happen to be one of them, only because I think some tend to burn out faster and I don't think they are very attractive birds, but they do lay well and they lay very large eggs. I'd never pick Cochins as just layers because of the broody tendencies, the egg size, etc. To me, the top three best layers are RIRs, BRs, and sexlinks (though I don't like sexlinks much) Some Wyandottes are good layers, some just aren't what I'd choose specifically as a layer. The BLRW variety can be great or terrible as layers, depending on the strain.
I have read some not so great things about Javas as layers. As heritage breeds, sure, they're great, but if you want a really consistent layer, I'd go with the more common ones.
I've said none of my BRs have ever hinted at broodiness, but helmstead has one who is a regular broody. There are always exceptions, but overall, they are not the broody type.
***I have heard that BAs are great, but I do not have any of those, so can't give any personal experience.