hey, hope you don't mind me chiming in... it sounds like you might have low progesterone which can cause spotting before your period (not the only cause of spotting, but one possible cause). The provera might stop the spotting from happening, but I don't know if it would really help you in the long run at all.
If they want to boost your progesterone after ovulation to hold off spotting and increase your chance of conceiving, provera is not the usual method. Usually they try clomid to give you a stronger ovulation and therefore a stronger corpus luteum cyst to make progesterone... or they give you progesterone suppositories to artificially keep your levels up (and the progesterone supps can be continued through pregnancy and are commonly prescribed).
I had low progesterone and a 12 day luteal phase with spotting for 2-3 days before my period. I insisted on a progesterone blood test and my levels indicated ovulation, but were lower than the average/minimum they like to see.
They were low on 4 consecutive cycles, even the 50mg of clomid cycles, but my GYN wouldn't give me a higher dose of clomid or progesterone supplements to take after ovulation.
I switched to a fertility specialist who said the first thing to do was to try a higher dose
of clomid... got normal progesterone for the first time that round and got my BFP.
hope some of that helps... not sure what country you are in but I'd be help any way I can!