I know it's nice to make a great sounding hoot and there are a pile of good inexpensive hooters out there. If you are looking to hoot for locating purposes only, try to get decent at one good final note of the whole "who cooks for you, who cooks for you all" sequence with your voice.
I have a bunch of trophies that say I used to be able to sound like a barred owl but in the woods it matters little to none. When hunting, I rarely ever crank out the whole sequence. Just one good sharp hoot gets the same response. Plus, they don't gobble in the middle of all that noise and leave me wondering where he was.
Even if you use your Harrison, try sticking to one note and see how it does for ya.