Which pistons?

This summer it will be time to rebuild my 273. Like many before me, I would like to rebuild it as a Commando, or at least something much like it. My machinist has done this before and he's more than competent. But he tells me that the biggest problem is getting forged pistons, and even then I need to decide whether to find domed or flat pistons.

So here's a question: Does anyone make forged pistons for my 273? Should I be looking for domed or flat?

I'm not looking to go nuts with the car. I'll never race it, but I would like to get what I can out of it without losing much poise.

Thanks!