First, I am assuming neither of the HELOCs that you are describing are fixed rates but are both variable rates (one with a 5 year draw period at a lower interest rate than the one with a 10 year draw period at a higher rate) since it is rare to ever find a HELOC with a fixed rate other than only for a short initial teaser period if offered, but those normally only last for 6 or 12 months.  

to date, the argument is that the income generated from short term rentals is so highly variable no lender can bank on an amount provided by the borrower, even if the borrower provides a plethora of documentation another supporting evidence.The only possible wiggle room would be if a certified general appraiser uses other similarly zoned motels, hotels or the sort.

If you use a HELOC, it will be a variable rate, but you won't have to make payments until you actually use the money.

If you have to go to some crazy variable rate product to make the deal work with rates this low, then the deal is most likely on the margins already.

Anything that is variable, like overtime, bonus, or commission will need at least a 6 month history at your new job to calculate what is usable.  

Variable costs are factored in as well. 

Not to mention that its a variable APR that is already at its minimum amount and therefore has only one direction to go; -up.  

This can be a better metric because is includes more variables.

The equity you have in your house really isn't doing much else for you so I'm a fan of using it wisely.The downsides are:You're dealing with a variable rate so if you carry a balance it can go upYour lender can reduce or close your line at any timeIf you default, they can foreclose on your propertyDownsides being said, I use two such LOCs myself to finance deals.

You will need at least 5% down payment for a new conventional loan but this could work if you are cash flow positive on your first property.There are many variables to consider here and you will need to run the numbers to know for sure.