Sleep Trainer in SG without CIO

Hi mummies! My LO is 7 months and has trouble sleeping through the night. He has reflux, so he tends to drink lesser per feed but more feeds through the day, hence he still wakes up 3x for motn feeds. Recently he has also been waking up/fussing when it is not yet time to drink. Im worried he is understimulated or i am not catching his wake windows properly in the day. How do I go on calculating his wake windows? Is there also any sleep trainer or courses who can help me understand how to calculate wake windows and how to adjust timings? I dont mind sleep training but i believe in attachment parenting and dont want to use the CIO method.