Just using years of experience and without looking at any charts or computer programs I know a 500 spine is way too stiff for her so she should be shooting something closer to a 900 spine. Now finding that in the weight you want might take some time and cost some serious coin.
About the best I can come up with within reason is Gold Tip's Ultralite 600 or the Entrada 600 if price is an issue. I believe the shaft is 5.7 gpi. With the shaft cut to 25.5", three 2" feathers, standard nock, and a 35 grain Nibb they should weigh right at 199-200 grains. They're still going to be plenty stiff so you might want to add Gold Tip weights to the back of the Nibb.
I shoot these with a 35 gr tip and 10 grain weight for a total of 45 gr and the total arrow weight is 209 gr. I shoot these out of a 26.5" DL FireCat set at 42# and am getting 275 fps. The FOC isn't too high, but at just under 8% it's enough for 3D target arrows.
You'd be best off checking some of the Carbon Tech Cheetah arrows or Easton Redlines (if you can find them). Considering what you are trying to accomplish you need to look at arrows that weigh in the neighborhood of 5.5 gpi.
Maybe somebody with OT2 can confirm the proper spine, but you can also look at Easton's Target Shaft Selector to get a better idea of spine requirements.
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