what size tent should I use?

Hello everyone.
I have 1 autoflower plant going right now.
She will be 3 weeks old sunday.
She is growing like crazy.
I have had her under 4 26w cfls from start.
I have a 2ft x 4bulb T5 with hortlux powerveg bulbs.
I was wanting your thoughts on what tent I should be using for that size light for 1 autoflower.
I have a 31x31x60 tent and I have a 24x24x55 tent.
Which tent would you use?

The tents are almost the same size. 7" here, 5" there.

Honestly....flip a coin.

Taller tent is always the winner in my mind. While you might not need a bigger footprint, the height is always useful.

both!!! pop another bean!