Forum:Scrap-iron Scarecrow & Tuner/Other Monster ratio

Ok 1st: Can you use Scrap-iron Scarecrow over and over in one turn or follow the Show's rules once per round?

2nd: Is it good to have 10 Tuner Monsters out of 23 other monsters (10/23) (not including Synchro or Fusion) and those 23 monsters out of 60 total cards (23/60)?