No problem - I understand the limited time. I'm trying to manage growing my Steem with the plan to live off the income here similar to you and am managing a freelance marketing business, taking care of my son, and live streaming games as well!

And yeah, it should look okay on Steemit as Steemit uses a slightly taller size for its images. Busy is a popular alternative to Steemit though, so I'd definitely recommend taking both platforms sizes into account. You want to be offering a similarly great experience on both sites!

Also, you should consider using busy. I use it primarily because of the cleaner interface and notifications - which are a god send. The only thing I still use Steemit for nowadays are wallet functions. Busy's wallet is a bit behind Steemit's.

Good luck on your journey to retiring with Steem!