L.S.
I made myself crazy thinking I needed to put my baby (now 6.5 mos) on a schedule. He just wouldn't do it! I was spending so much time stressing about this, I was forgetting to enjoy the baby...
Everything changed radically at around 4 months when we decided to just not worry about it and let him sleep whenever his body told him he needed to. At the first sign of a yawn/eye rub I would switch gears, make the room a bit quiet and boring, start swaying, etc. and he would fall asleep. Some naps lasted two hours, some lasted 15 minutes. Didn't matter. Once we started doing this, he started to sleep for longer stretches at night. And once we began solids at 6 months, he started to sleep through the night most nights, though he still wakes up sometimes to breastfeed.
One thing that helped alot -- we bought the book "The 90 minute sleep solution" which helped us see that it isn't the length or timing of the nap that matters, rather the length of time they are awake between naps. I highly recommend this book.
I think we forget that our bodies and circadian rhythms exist for a reason -- yoru baby is growing in fits and spurts and one day she may need something different than the day before. If you can, let go of Weissbluth and all the others on this issue and see where it leads you.