Reddit mentions of O'Dells Popcorn Supur-Kist II Topping (Gallon)

Adding to your great comment for Whirley-Pop no fail amounts:

• 1/3 cup unpopped kernels
  
• 2 tbls coconut oil
  
• 1/2 tsp Flavacol or fine salt
  
  Heat the Whirley-Pop and oil until hot. Add popcorn and flavacol. Stir occasionally with the handle and remove when popping nearly stops. Add to a large container and and if needed, add a hint more Flavacol to the popcorn.
  
  Bonus: Add ODell's Supur-Kist topping or Snappy Butter Burst for butter flavor.
  
  

You've just about got it. You're correct about real butter soaking the popcorn and making it soggy. However, I'd avoid Reddenbacher's oil in favor of a dedicated topping -- don't use one that serves double duty. Get one like this or this. This is actually better, because it's made from butter. You can make your own topping by making ghee.

For the popping oil, if you want the best, use coconut oil. There are butter-flavored coconut oil products like this, but even plain coconut oil from the supermarket is better than Reddenbacher oil.

When you're ready to become a popcorn wizard, step up to the popcorn hammer. :)