Be mindful of short-term capital gains tax, as profits from flips held for less than a year are taxed as ordinary income, and frequent flipping may result in self-employment taxes.While profits from flips do not qualify for 1031 exchanges (since flips are considered inventory, not investment properties), you can minimize your tax burden by deducting allowable expenses like renovation costs, loan interest, and holding expenses.If you're considering diversifying into rentals, explore opportunities to benefit from long-term tax advantages such as depreciation and lower long-term capital gains rates.

The owner should look at it more like a DSCR, and should be pricing the property and offering terms such that the income from the property is adequate to pay back the loan.

In the past two years we have completed over a dozen flips, We are holding 20 rental units self managed and 2 self managed Air BnBs.

On the plus side now I will have a recorded Certificate of Occupancy with the city, as this property will be a long term hold for me most likely.

These are what we call "A-class" markets—areas with strong fundamentals, high demand, and typically excellent long-term appreciation.

Quote from @Brendan Jones: When it's a home you intend to live in, I lean towards focusing on what you want, then making it work as best you can as a short-term rental.

Short version...

A HELOC offers flexibility and lower interest rates, which can be ideal if you’re looking for short-term financing with lower payments during construction.

With that being said, if you're comfortable with a long term hold, San Diego and especially coastal, will always be attractive imo. 

The plan is to buy and hold.