Well, I'm gonna try my best to help you and your Yanma.
To determine whether its a waste of time or not depends upon the use you want Yanma to have.
If you just want to have it for fun and an occasional battle than this is what I would do:
1.) For good moves, pick out a few and then find a pokemon that learns these moves. Instead of Venonat, use a Volbeat. Teach it: Signal Beam and Double Edge.
2.) Take it to the Pokemon Daycare.
3.) Breed it with your female Yanma and get an egg (or 2, or 3, or however many you want)
4.) Hatch it and give it an exp.Share, and train in a hard spot with a high lv. Pokemon
5. It should level up fairly quick and learn Bug Buzz.
Togekiss will work for a Flying-Type pokemon.
So, hears what I would do for a moveset:
Yanma @ Choice Specs
+298 Spe, -110 Sp.Def
Giga Drain (To get HP back)
Bug Buzz (The whole Reason)
Air Slash (Coverage)
Onimous Wind (Coverage)
I hoped this helped and answered your question!