I did this and don't regret it; wish I had done more but it's nerve wreaking at the time.

I think the max you can do is 50% of the value or up to a certain dollar amount. Payments come out of your paycheck. If you have good job security I'd say go for it. If you did ever lose your job you would have to sell the corn pay taxes and pay back the outstanding loan. My 401k allocation is $0/0% and my contributions now basically just go towards paying off the loan. Your employer if they have a 401k match should also be matching your loan payments as they occur.

It's also hard to get a hunk of corn and having that much money on an exchange is another worry. Hopefully the money transfers and all settles fine. Do it in small few thousand dollar amounts.

Usually involves some paperwork between you, HR and your 401k provider. Need some signatures and pencil pushing.