My memory is awesome...just a little short...

The downthrust you specified seems pretty high, but...a lot of times a flat bottom / high wing trainer (especially if it has a low thrust line) will have a wild pitching tendency unless addressed through the prodigious use of down thrust. In other words...it'll want to climb like crazy "WFO" , etc. If you trim that out, then it will dive like crazy in a power off situation. You can't win like that. In an attempt to "neutralize" the models behavior, downthrust is used.

The Dihedral you specified (3.5 degrees/panel?) is not at all excessive. The effect of dihedral is rather complex, but...

The lift component developed by a wing acts perpendicular to it's surface. In a "V" situation as is presented by a wing with dihedral, the lifting forces are acting upward, and inward.

Let's say now that the plane banks. Now, one wing is level and the other is tilted upward at a rather high angle. Now, the vertical component of lift between the two halves of the wing is quite different! (total lift is the same)

The lower wing is producing a greater "vertical" (less horizontal) component of lift than the high wing (more horizontal and less vertical component) and thus the aircraft attempts to revert back to level flight. Obviously, a desirable trait in a trainer!

Go with the specified values. Make small changes if you feel they are necessary after a few flights.

Good to hear you are getting "Momma" involved. Good thinking!

That way...a trip to the field is a "family night"!

Have fun!