Regarding Va it has to be noted that there are two different aspects which define Va:
The first as has been already pointed out is the stall.
In this case the risk of exceeding the structural integrity via dynamic maneuvering is limited to some extent, as the wing will stall at that angle no matter how dynamic the entry is. As has been pointed out you will probably still be able to destroy your aircraft using clever combinations of loads. But it will take significant effort.
The second aspect potentially defining Va can be control Authority. (However, this usually doesn't apply for an aerobatic plane).
In this case for instance the Elevator or Rudder authority does not allow to exceed a certain amount of Pitch authority and thus AoA at a given speed, i.e. g load.
This limitation has the distinct disadvantage that it is by no means a 'hard' limit and can easily be circumnavigated by very dynamic handling, i.e. reversals.
This is also how the famous AA587 shed its tail below Va.
In a control authority restricted Va aircraft it will be much much easier to shed some imporrtant bits'npieces than in a stall limited Va craft.
So it might be a good idea to check what factor determines Va in your aircraft (and for which axis) to know what particularly to avoid.
Last edited by henra; 20th Jun 2011 at 20:11.
Reason: clarification amended