How much to water green giant arborvitae in 2nd summer?

They were planted in October 2020 and are doing well. They are 5-6 feet tall. I used drip irrigation on them last year with a small circle about 6 in inch radius. It was roughly around the edge of the root ball.
This year I added another dripline about 1-2 feet further (8-feet circumference) to make sure I'm wetting where the roots have grown I want them to grow. It is also about how to side the trees are now (3 feet or so).
In total, I have 24 0.5 GPH emitters on these lines. Last year I was shooting for 20 gallons per week (unless we got some good rain of 1"+ and would supplement based on soil condition).
Green Giant Arborvitae trees are bigger now but also more established.
What would the watering need be?
Also, do you think the roots have grown the extra distance at this point? Should I remove the inner ring entirely or leave both?
In the future, worth just keeping this drip irrigation installed even for entirely established trees? It's already there. I'd have to perhaps rethink the emitter locations when the trees get way too large to be putting water that closes to the base. But if there's a dry spell, easier to use this than go sit with a hose. Even mature trees can suffer from dry spells.
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