For the main event, there is arena in the setting in diverse stage.
Have you thought about the 1800 hp version one ? We had good discussion after moa5, where viper (who is also moa3 and 5 winner) and most arena experts said opinion about 900hp wall in arena (Stefan melkor Miguel me..)
After all is depend on what aspect you wanted to be shown by making arena a sett map, but if it’s the real arena aspect which are strategy decision, build order, adaptation, preparation etc like it always was, then I think using the 1800hp version should be better, if it’s to see some trush festival which remove all the aspect said above, then arena is fine.
We will be using Arina. Next handbook update will specify this, and the mappack has been updated.