I've been absent from the forum for a few days as I've been doing seminars and events for Mossy Oak and Hoosier HunterCustom Calls. I've been a master call maker for some time now, and making custom single piece box calls for quite a few years, so I'll give you my insight into the boxcall questions you have raised.
Oak can be a quite good box call, and mainly because of the density. Diferent wood species require different thicknesses of the sound rails, because of the density and grain. When I build a box call I work within thousandths of an inch, not fractions of an inch. As a rule the straight to quartering grain woods work very well and the softer the hardwood the easier to get a yelp. The paddle must be as dense as the box or denser for proper sound and tone, take for example, Mohagany box w/ Purple Heart paddle or Poplar box w/ Walnut paddle. A quartering grain will generally enable two different yelp tones, but this may be attained in other ways also. In my opinion a cedar box should never have anything but a cedar paddle, just because it would be ugly. A cedar paddle should have no white wood in it, because it adversley affects the tone and pitch.
As far as wet box call paint, well,I would suggest you learn to blow a mouth call that will get the job done cause I've never heard a good box call with the stuff on it. The first requirement of a box call that I craft is to yelp, cut, and purr without chalk! If it don't, it don't get any further work.
Good Luck, God Bless, and Stay Safe!