re: what (in your opinion) is a reasonable amount of SL debt to incur?

Take out as much as they'll give you. (But put it in the bank or short term investment, spend as little as possible), then when you get out you'll have <3% loans to start a business, buy a house, etc. (assuming student loan rates are still that low? I've been out a while so not sure)

*unless you're not disciplined enough to not blow through the money. Then get a job and take out as little as possible.