I have to replace the 6 panel solid wood fire door that leads from my garage into my house (the current one is slightly warped). I plan to use an Old Masters stain (to match the rest of the woodwork in my home). Is it okay to lay the door flat on a couple of saw horses and do one side at a time, or is it much better to stand it vertically and do both sides at the same time? Also, what sealer would be the best to use for an entry-type door like this one? Will the sealer go on and dry nicely if I brush it on as I don't own a sprayer? Any help would be greatly appreciated.