Nosing over on take off doesn't indicate anything about the c.g. The 'vanessa rig' and all of that jazz is nice but you don't need it. Just measure your MAC and calculate. Do this: put a bubble level on your stab at 'zero'. Use a triangle to measure where LE of fwd most wing and TE of rearward most wing are located on the table normal to the line of flight. It doesn't matter if your wings are staggered. Calculate the balance point at 25% from LE of the combined wings LE to TE measurement. That's it! If you have plenty of elevator throw and area then move the balance point forward a little. Short coupled aircraft or those with tiny stabs (think sailplanes) required a little more accuracy. 25% MAC is a good starting point.