Fitter 35

Looking for feedback from those who have tried fitter 35 from Purina. Does it work? Is it worth the cost? How long do they need to be on it to see results? I have a heifer getting ready for a show/sale in 6 weeks and she's about where I want her now. I don't want her to get too fat or course fronted. I've adjusted her feed but don't want her to lose her bloom and muscle tone. Right now she's getting about 6-8 lbs. of a grain mix similar to AAOK's famous mix. I'm adding some full tank and a scoop of full body pellets from Sunglo (which is similar to precon from purina). I'm also giving her about a 5 gallon pail of silage per day to help fill her up and free choice grass hay. Any other ideas or tricks to hold a heifer and keep her looking fresh? Thanks.

I've not presonally used Fitter 35.  I've used winning fill to hold calves before and it does pretty well.  Of course hulls are always a good filler. 

What age is she? I know folks who just kick older heifers that are border line getting stale out on a round bale and a stress tub and bring them back in on full feed about 2-3 weeks out.  The calves look fresh and it really does wonders for a heifer that may be getting a bit full in the brisket and neck.  When I say older I'm talking senior yearlings.