Kittens under four weeks old should be fed every 3-1/2 to 4 hours during the day. Nighttime feeding may not be necessary as long as the kittens are fed at least four to five times during the day, but if they awake in the night crying, they may be hungry or cold. Just like a human baby, they will need some attention here
During the first week, feed the kitten every two hours. During the next three weeks, feed them every three hours. When the kittens are four weeks old, they can be fed every six to twelve hours depending on how much solid food they are already eating. here
we've found it is easier to start young kittens off using a plastic syringe (without the needle of course!) instead of a small bottle; it's easier for us to control the flow of the formula and even be able to give it drop by drop if needed. From the newborn stage until the kittens are about 1 1/2 weeks old, use a 3 cc. syringe, and feed every 2 hours. At 1 1/2 weeks old, they are ready for the 6 cc. syringe size and feeding every 3 hours, and at about 3 weeks old, move them up to a 12 cc. syringe, feeding them at least every 4 hours. An average meal for a 3 week old kitten can vary from a single syringe full (12 fluid cc) to three syringes full (36 fluid cc) for a large and hungry kitten!! ........ A steady weight gain of about 10 grams (or 1/3 of an ounce) per day is recommended, but do not be surprised if a kitten may stay at the same weight for a day or two, then suddenly the weight gains are seen here
Feed them until they are full. During the day feed every couple of hours. Kittens will usually sleep through the night after their eyes are open. (approximately two weeks old) here
Advice varies a bit but sounds like you can at least drop back to 3 hourly round about now...