Help with 18 week old sleep training!!

Started sleep training at 16 weeks. Saw dramatic improvement the first few days… went from up every 2-3 hours crying to falling asleep independently and zero wake ups the 2nd night. Then throughout the first 7-10 days crying got much better. But now, it feels like I cannot get her sleep just right otherwise lots of crying… early morning wake ups… false starts etc. We do about 1.75 wake windows all day with 4 naps. First 1 I hold to extend because she isn’t connecting sleep cycles yet and then 3 of them are short. The nights I’ve done shorter wake windows before bed seem to be the nights she cries the least. But then everything I read on here says she needs more wake time to get the sleep pressure right. HELP!