I would like to suggest that the TeeDee .020 be added to the menu of engines.
Reasons: The hollow log events survive mostly on old engines that are no longer on the market, and the supply of viable .049's is dwindling. At the same time, there are (I believe) quite a few TeeDee .020's sitting around with nothing to do. While the TeeDee is a high performance design, it's only 40% the displacement of an .049, so it won't be any threat in horsepower.
Most hollow logs list engines down to .020, but a PeeWee is so far below a Black Widow, that nobody (that I've seen) has given it a try. The menu already has several rotary valve engines, so this won't be a first.
The standard seems to be "nothing better than a Black Widow or a Fox", and I believe the Tee Dee .020 is within this limit.
If this engine brings in a few more entries, it's a good thing.