Clear Penetrating Epoxy Sealer
I've used, and really like, smith's penetrating epoxy, coat till it won't absorb any more, then lay 5-7 coats of a good exterior varnish.
The smiths is a two part, looks like water, really soaks the wood well. Last time i used it, I could only get in in gallon drums, but ibelieve you can buy small batches now. I liked to mix up a batch in a glass mason jar. When you are coating a small area, you can save unused epoxy. I put unused portion ( tightly covered) in freezer as soon as I'm done coating. I let the wood cure overnight. In the morning, allow cold epoxy to come up to temp with lid off before using again. I'm in Texas, so I think it was about 20 minutes. I never used same epoxy for more than one overnight, so don't know how long you can get away with that technique.
Nice thing about the penetrating epoxy is that it will strengthen your tiller, I don't think I'd bother with epoxy unless it was a piece that needed to be durable, or it was showing signs of rot. In other words, I wouldn't bother epoxying healthy eyebrows.
Hope that helps.