Just found this thread and found it funny that I replaced my golf balls in the same way, except I didn't use the tees. My originals looked horrible. The tees didn't all fit right, the balls looked like they were put on by a blind guy and the glue was everywhere. There were also 4 different kinds of bulbs lighting them. I think the bag of pratice balls cost about $1.50 from Walmart and the little black sleeves I put in the holes I drilled cost maybe $1 from the local hardware store.
teed off golf balls orig (resized).jpg
teed off golf balls (resized).jpg
teed off golf balls lit (resized).jpg