• I agree with Jeff. It's a guess, perhaps WAG, if you have no history.

    2GB (4 x 500MB) or 4GB (4 x 1GB) is a decent guess if you can spare the space. I'd also do a 500MB or 1GB log and monitor.

    5GB is not a lot of space these days and even if it's overkill, it prevents issues. I would monitor usage and watch it over weeks/months.