That's lovely! finding a hollow log saves a lot of work.
I'll have to try that kind of mallet. I heard they sound best if you shave a buffalo ass in a full moons night. No buffalos here, though. I might have to find another source of hair.
Drums are a great thing to make, It's quite a process and they really come alive when drying. I bet the first drums where made a loooong time ago and it was fun already then.
You might like the book "musical instrument design" by Bart Hopkins, it's nicely priced and absolutely packed with things to put on one's to do list
