In your case you are truly looking for a "condo on the water." Since you will be working 60 hours weeks, you will mostly be sleeping on the boat. You will not have much time for "house keeping." I am normally a smaller is better guy, but in your case, I think you need a boat a bit bigger. You need two spaces: A "private" space for your stuff, and a public space. If you get too small of a boat, you will have stuff everywhere. If this happens you will never actually sail it on weekends because getting ready for sailing will be too much.
You will have a reasonable income, so I think a smart plan would be something like:
Buy a 10 year old Catalina or Beneteau 36. There are a million of these on the market. You should be able to pick one up for about $75K. This would make your monthly payment (including insurance and slip fee) about $1500 / month (financed over 8 years). Add twice a month professional cleaning and electric and you are looking at a total outlay of < $1,800 month.
When you finish your residency, you can at least recover what you owe when you sell the boat, probably even do better than that. If you decide to keep it, you will be able to pay it off in short order.