Shakes head. Ummm Maelocks...you contradict yourself. What a surprise.
Your last sentence. If you saw her on the bike. That is what a fitter does. Can't this up..lol.

I have been doing fittings for 25 years OP. Word to the wise, be very weary of advice you get on the internet. ^^^^

If you want your best fit, ask your local bike club who does the best fittings in the area. If your bike shop can couple this to your purchase for a discount, all the better.
Fit is king. Unless you are a savant, your chances of nailing your fit algorithmically are slim and none and slim rode off on his bike.