If anything it just means that initial newbie tax / buffer is going away. 

Many cost segregation study professionals will offer you a free quote on the cost of the cost seg study specific to your property as well as the potential tax savings.HOW LONG DOES A COST SEGREGATION STUDY TAKE?

Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

I would recommend an STR for the best tax benefits and cash flow no doubt.

Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

I have 2 options:- finance the construction pre-selling the apt, and take my profits (expected to be around 700K pre-tax); or- finance the construction with a 6-7%/year loan (collateral = my house), keep the 10 units, and once the building is completed in 24 months, rent them for circa 180K/ year gross.

Have also used list source and prop stream before but the data they provide is very similar to what I pull off the tax records through CRS Tax. 

Check with your tax professional about your ability to deduct the interest on a HELOC from your taxable income.2.

Most are traveling professionals needing an alternative to a thousand dollar a week hotels.

@Andrey ShostakA tax calculator would be nice.