How many Hours would you recommend for practicing drums?

It's not too much about the time invested, it's the planning of your practice time what can make you progress faster. Depending on what you're practicing, it's a good idea to organize your study materials in order to cover many different learning techniques. For example, you could prctice sight reading on monday, paradiddles on tuesday, 4-way coordination on wednesday and so on. Also, you could practice different exercises for small amounts of time every day. Remember that no matter what you practice, the idea is to apply your drumming knowledge in a musical context that makes sense.