as long as the wing is strong enough - don't be concerned
measure the total chord and total thickness
The thickness at highest point will be -likely 12-10%
using 6-8 lb A grain GOOD balsa and attaching with Gorilla - -a thin combed coat - the strength should be fine
using lighter wood -the balsa strength goes downhill- fast -
As for going faster - forget it -the % means little
But if you keep the plane light -it will be overall- a much much better aerobatic setup
Weight is THE enemy Many of the plans in that size are extremely heavy for the size .
It is physically impossible to build that design too light or with a wing too thin
And the landings will get easier with the lower weight
I have done the ARFS of this basic design for magazine article yers back and typically they suck- too heavy
But scratch built with low wing loading- a terrific model.