How many Facebook messages can I manually send per hour without being banned?

I'm looking to manually message my website URL to a select group of people via Facebook. This isn't some elaborate project that is going to require a bot, but I'm looking to get this URL to about 2000-5000 people. I have all summer and I sit at a desk for most of my mornings, and I'm looking to get it done over a course of a few months. It's not a scam or anything sketchy - it's a legitimate e-commerce website that has a very specific market. So, with a select group of people already in mind, I was thinking about manually sending out 20-40 messages an hour. Am I going to run into a problem?

Facebook states that you can message 250 people at once. I'd be more cautious as I've read that sending max 5 message per hour is recommended to avoid getting labeled as a spammer and to customize/reword your message as much as you can.

Its very difficult to send 5000 msg manually, instead of that just make a 3 to 5 new profiles with sexy girl pictures and put on all required details then start share your website as your status with some interesting conversations when you got 5000 friends and some good subscribers on each profile.

It also depends on how many people complain about you as a spammer. If your message does not appeal to many, then you will be banned long before reaching the limit.