You need to know some of the physics involved in order to know whether the stays are required. Of critical importance is the strength of the mast itself under side loading or a bending moment.
My own mast came to me with an aluminum base (tabernacle), Aluminum pipe mast and boom, (too short) stainless shrouds, two per side. In order to eliminate the neck height shroud that interfered with access up the flybridge steps, I moved the mast step to the lower deck (top of the aft cabin) and put a fastening on the edge of the upper deck, where the original step had been located, to hold the mast in a vertical position. The relocation gave me the opportunity to add several feet of height to the mast and length to the boom.
I add temporary shrouds opposite to any load over 50 lbs if I am using the lifting boom. Otherwise, I am happy with the unstayed aluminum pipe. It carries lights, spreaders, flag halyards, radar, radar reflector, boom and all boom rigging, but no shrouds. I made the change to unstayed more than 20 years ago, so it has stood the test of time.