Optimal loop temp and sizing question

Brian V

Hey all,
I'm getting ready to replace my single pipe steam system with a hydronic system and have a couple of questions.

Boiler design temp.....

This will be an oil fired 4 section, will also be using an indirect for my domestic.

What is the optimal loop temp? The manufacturers I've been looking at all give a range that they will operate at, but what is best for the boiler? When sizing baseboard, what temp do you use? I do plan on using a reset control, maybe not at first but definatly down the road sometime.

Thanks all,
Brian