Ahh yeah I forgot how messy they are - even the little guys. There will be food and seed hulls on the floor, feathers on the floor, and poop on the floor and walls. The good thing about bird poop (haha who knew there was anything good about poop?) is that it normally is odorless and it's also easy to clean up (compared to other animal poop).
I never liked seed skirts that you add onto the cage - the seeds always got stuck between the cage and the skirt. My canarys cage had a built in seed skirt and that worked well.
Also, be sure that the door(s) to the cage are convenient. My canary cage only had one large door that swung open to the right, and since he wasn't tame trying to get him out of there was awful. It was also very difficult to work in the cage changing out perches and toys without him trying to fly out to get away from my scarey arm and hand. And the budgie cage was so big it was nearly impossible to catch them. I would suggest multiple openings of various sizes. You'll also want a cover for the cage for bedtime.