I have an old Radio Shack 1850 Electronic Chess Computer, which I would like to know the ELO rating each level plays at. The instructions just give average number of seconds per move.
I figure I would play it against tChess Pro on my iPad, which the engine can be set to a specific ELO rating. When I find they are both winning about the same number of games I can check what level tChess is at and that will be about what the 1850's rating is.
Question is, how many games would be a good sample before I make that call? Obviously if one dominates the other, I'll have to tweak the levels and retry.