Irrigation layout

Hello. I'm wondering if people can share their thoughts on layout of irrigation lines please for a garden bed.

There's 4mm lines in at the moment. They run off a 4mm line, it's been in a couple of years and it just doesn't work too well. Not enough pressure and I realise my mistake.

So new things bought. This time it will run off a 12.5mm line (1/2") which is standard hose, with 4mm lines coming off. I've drawn out a diagram and trying to decide between two different layouts for which would work best

Purple line is 12.5mm hose.
Black dashed line is 4mm line with drippers.

The site slopes down hill and is fully planted .
next to it is a small veg bed, which I can maybe incorporate into this irrigation or maybe just do it separately

Any thoughts on layout before I start work on it please? Thank you

 

I can't really help with your question as my experience is limited.
I did have a Gardenia watering system probably about 30yrs ago with all sorts of jets and sprinklers attached to water my flower beds - about 70ft long and 6-8ft wide each.
It was a lot of faff trying to get it balanced but I sort of got there in the end and it worked well - for a couple of weeks, then jets got walked on by foxes, badgers or something. Birds would dig around and cover them etc etc, so it needed frequent attention.
The following year when digging I damaged so much of the pipework which had disappeared underground I stopped using it.

It's a lot drier here now than it was 30 years ago so a few years ago I got some 50m soaker hoses and they have been fine and do a good job. I have gone through a couple with a spade which is annoying, but it's quite easy to join back together.

Your plan looks fine in theory, but it would be worth testing it to ensure you have enough pressure and an even drip along the length, before properly installing it.