while branch design is standard loop design is becoming more common because of it's ability to maintain even pressure through the length of the loop. an additional thing you might want to look at is making each branch to the raised beds it's own loop as well. this may prevent later problems with spotty coverage.

I see... so loop design have advantage over even pressure... If that is the case, I will take your advise and design smaller branch off loop to individual raise bed.

Having to say that, does loop/ branch design have any impact on water flow rate? Sorry if my question sound stupid....

sorry, been offline for a bit. to answer your question while my personal preferance for micro-spray's can be affected by branch design the flow rates of a loop design with pressure regulated drip lines will not change.