I played from the bottom up, 0 realism. I'm only at 28 realism now and still pretty happy with my progress. Hey it's only a game, meant for entertainment, not judgement. The posters were only suggesting that you crank up the difficulty level if you felt bored roaming around the Pacific sinking everything. Being God can be longly

If however you don't find these suggestions useful, ignore them and continue to be the tonnage king--it's not like we can predict which way you'd prefer.
Anyway, have fun.