How to efficiently grind for units in arena?

I know this might sound like a stupid question. But I need around 600 units more to buy the first July 4 thronebreaker deal.
I'm thinking of doing arena, which I usually never do. My question is which arena should I do, currently I can see there are 3 arenas. Or any other tips to maximize the units you get from arena would be great.

Comments

Vendemiaire

You can technically get 400 units this weekend if you have an decent size roster.

135 units from the Featured 6*
Use the low rating 5* champs to build then use all of your 6* champs. Twice today, twice tomorrow.
135 units from the Basic 6*
Same but only 5*s.
130 units from the Summoner’s Trial (up to 1.5m).
Same but only 4*s.

That’ll net you around 100k battlechips too. Pretty good chance you can gain 200 units from that.

Goodluck!

ChiliDog

Right now 6*'s will give more points to 22 hr event, which has units at tier 4. Also 6 or 7 matches of 4* arena will give you 39 units pretty quick.

If you haven't completed 1 pass through all monthly quest difficulties then do those.
Set your 6* champs in on autoplay for whatever quest is going on...like mystic use, especially the 1 energy per move ones if you don't have refills in backlog.

Kabam Valkyrie

Moving to the correct category

The_HoTU

Thanks for the tips everyone, pulled a 6* red guardian from the bundle's 6* hero crystal pretty decent not great though.