I use rubber mats and have shaving as my banks. It will cost you at first but in the long run it will save you money. You should think about it in your case you could us straw for your banks.
I change my horses rugs at night. I just think about it this way if i was out in the rain all day i wouldn't like to keep a wet coat on.
Some rugs when wet can be heavy.
I have many winter rugs so if the horses has been out for 8 hours in the rain its just nice to put a dry rug on the next day.
I had a horse that weaved I went and put a grill up and she didn't do it as much. A friend said she seen her stand behind the grill and was weaving what a wast of time that was.
Your horse would be so happy out in the field.
Think of your horses health, She looks good for 20.