I set up a slightly over ambitious PVC drip system a couple of years ago and I'm very interested to track your progress - seems very similar to mine. I basically ran a 3/4 main trunk line through my garden, and branched off with 1/2" pipe to each bed or area. I had a ball valve at each location, so I could pressure the main trunk and water whichever areas I wanted. I even pre - drilled additional pieces of pipe for each bed with different hole patterns to accomodate different plant spacing, and labeled each one to make for easy swapping when needed. Unfortunately, I didn't clear water out of the main trunk during the first winter, and the pipes burst in several locations - I should have known better!
A couple of my observations - I have municipal water, but I have no idea what the pressure is. I glued my 3/4" connections, but simply pushed together the 1/2" connections in the bed areas. I read somewhere online that the water pressure wasn't enough to blow the connections apart in the 1/2" pipe - seems to be true! I initially ran a 'sub' trunk for each bed, and then a lateral line for each plant row within each bed. I quickly found that the pressure quickly lessened the further away from the ball valve that the holes were. By connecting all of the lateral lines on the opposite end of the initial trunk, the pressure was better balanced and water was emitted more equally across the entire bed. The system was a little finicky - if I were to open the valve for one bed 1/2 way and then open the valve for another bed, the pressure within the first bed would drop a bit. It would take a little bit of tweaking the ball valves each watering to balance the whole system. Certainly not a deal breaker - it/s a fun project to work on and a challenge to figure out how to make improvements as I go.
I intend to repair the main trunk and then bury it this fall, as well as make a few other improvements as I go. I like the idea of burying pipe all the way back to the main valve at the house (about 50' or so away as well). Post some updates once you get back at it - I'd like to compare notes!