RE: Slowing down a PC-9
What Prop are you using?
I did the flap mods on one of ours and it was probably the biggest single help.
I thought they fly well enough to just fly them onto the ground at the speed. Scary at first (Maybe go on a buddy box with another experienced flier or instructor for the first couple of times) but good practice for some of the more wild planes that you'll no doubt have later.