mortgage for second home vs investment property

Hey guys a quick question. I live in Canada and want to purchase a second home in California to use for me and my family for vacations and to rent on Airbnb when I'm not using it personally.

Speaking with a cross border mortgage bank that will use my Canadian credit in a USA mortgage. If it's a second home I need 20% down, if it's an investment I need 40-50% down.

Just wondering what the min # of days need to be (that I need to live in the home) to be eligible for a second home mortgage.  

If I need to put down up to 50% I wont be able to do this and I dont want to commit mortgage fraud either.

Any advice is appreciated.

Thank you