I found the light fixtures at Lowes a long time ago. I love them - just because of the initial Wow factor when you open the barn doors and turn on the lights. (It is just the 'girl' in me!!) The previous flourscent lights were horrible because they did not want to work when the temperature was under 50F.. which is not that often down here, but still very irritating when you need light!
As for cleaning the barn: Once a year we do a BIG clean. I take the horses out on a low humidity sunny day. Strip the stalls down to the rubber mats. I use a water/amonia mix on the mats. I use a cobweb 'broom' with an extension pole to get the bulk of the spider webs out. Then spray everything down with a pressure washer. That gets rid of the rest of the cob webs and dust. This is a 1 day project ...and it helps if you start by taking a diet pill...ha ha !!! I do this in early Spring and try to time it right before any foals are born, if we are expecting that year.
We had a Barn Master metal barn in our former house. It started rusting less than 5 years after it was errected and the condensation in the tack room made it impossible to store anything made of leather in there. Here in South Texas, it is usual to have not only high heat in the afternoons, but very high humidity as well. Add cool mornings to that mix and condesation was dripping off of the metal walls... wood is much more forgiving.
We designed the barn around the fact that the minimum living area, per the building restrictions, had to be no less than 1800 square feet upstairs. There are 6 - 12x12 stalls, 1 - 12x18 foaling stall with a turn out, 1 - 12x12 wash stall, 1 - 12x12 and 1 - 12x6 open storage area, a 12x12 laundry room with 1/2 bath and 12x12 tack/feed room both of which are climate controlled. The center isle is 13' wide. We put both hot and cold water into the wash stall. The real blessing of this is when you are teaching a young horse to stand to be washed. Warm water verses cold acts as a tranqualizer and calms the horses down.
The plan was to live above the barn for about 5 years and then start construction on the house, leaving the barn apartment to be used as rental property... but then we found out Don was ill. We still do want to build our dream house, we are just now taking a much more conservative approach to it all. Here is an inspirational drawing of our dream house.. but with a grey stone exterior with black shutters: