My new-to-me 1990 KDX-200 needs 2-3 spokes replaced in the rear wheel. Many of the spokes are siezed but still tight. 2 are broken with only the nipple left in the rim. I'm concerned that with the age of the wheel (15 years) and my weight (250 with gear) that other spokes are going to become loose or break as I learn to ride the bike faster. Should I replace them 1 at a time or just plan to completely respoke the rear soon? Would the rim be damaged if I rode once or twice with the 2 missing spokes? It would be slower trail riding.