So about a year ago, I went ahead and bought a NES Toploader and went through the process of getting it modded with the RGB Board and even getting that 3d printed Multi Out installed in it. But then, being an idiot, I failed to realize PAL NES's were not like PAL SNES or Mega Drive's and that you couldn't just mod them with a 50/60HZ switch and get the proper speed. I only ever purchased NTSC Cartridges, and with the Console and the Mod, I probably spent 3-400 Dollars on it, so I really don't know what to do?
From reading PAL Snes still needs NSTC crystal to run 60hz at the right speed. Not sure if you can do the same with NES, never modded one
If you install a ppu, cpu and crystal from lets say a famicom you will fully convert your pal nes to ntsc.