Word of Glory Predicted Health

[unlimit]

So I made a Word of Glory predicted health feature (Thanks Crispii for the code!), only to realize after using it for the night that WoG has a coefficient with SpellPower and AttackPower (hurpdurp?). So, now I'm wondering if there's anyway to directly call to that spell and find out the exact amount, since it doesn't change unless there is a change in spellpower/attackpower?

Or maybe I'm thinking about it the wrong way.

Here's what I have so far:

function FracHealthWOG()
  local hpa = 2678
  local pta = UnitPower(uid, 9);
  local a = (UnitHealth(uid)+(hpa*pta));
  local b = UnitHealthMax(uid);
  if(b<1) then return 0; end
  a=a/b;
  if a<0 then
    return 0;
  elseif a>1 then
    return 1;
  else
    return a;
  end
end
wog = FracHealthWOG();

Also, would there be an easy way to automatically change PTA, which is either 1,2,3 (holy power) to 3 when Hand of Light (my mastery buff) pops up?

Thanks!