Bench to Bucket Conversion Advice

the outside mounts need nothing the inner mounts need reinforcement plates
Ok thanks. I see I can buy a set of 4 plates from JEGS for $30.
Stupid question...can I avoid welding them in by doubling them up (one inside and one outside) and 'capturing' them with the mounting bolts? It's my understanding that they are primarily for keeping the bolts from pulling through the floor pan. My suggestion probably sounds pretty hokey, but I don't have access to a welder.