Frank did build in class, and already had a version of the tail bits to show us, as did Jack.
We are "allowed" to build the tail feathers before next class. The vertical stab & rudder, and I think also horizontal stab & elevator.
In class we are making it as per the plan, but Jack & Frank had modified the build slightly, based on some comments in the write-up that hinted to the plane being a little heavier in the tail than necessary.
I cant quite remember if Jack built his as per the plan, but Franks tail was 28g lighter than Jacks, I think!

(p.s. You are right, on a PC Frank stays sideways, on an iPad he turns right way up!)