I am planning on making a simple stopwatch with:

• A display
• One or two additional buttons to start the stopwatch and stop the stopwatch and maybe reset it.

The problem is that it has to be as small as possible. With all those different Arduino boards out there, I don't know which one I should buy (mini, micro, nano, ...).

I am not sure how many pins I need for the LCD since I have read that in fact not all pins are mandatory for the LCD. I have done something earlier with an LCD and I found the pot meter for the LCD contrast level a bit of waste of space. Could I just replace it with a certain resistor or something?

How many pins in the end would I need and which board would be fitting for this little project?