The quality of the home surpass the quality that these other builder homes are making.

Even if it were new, they have no idea about the quality or manufacturing imperfections. 

The property taxes and interest rates are just eating away at the cash flow, so I'm pretty much stuck doing flips in that market.Wanted to get your advice and hear your thoughts on where might be a good market for the BRRRR method these days?

There's certainly other aspects that you need to consider such as pricing, quality of photos & overall listing, is it clean/repairs are done, if there's tenants are they being decent to people during showings, are you requirements reasonable etc... 

Some contractors have insurance, some are 1 man band with no overhead, quality of work factors into cost, level of finishes.We created a calculator for our clients to use here in Chicago, specific to our renovation pricing, but even that is just a guess based on some assumptions.If you can find a quality general contractor, pay them like @Bruce Woodruff mentioned, and it will make your life so much easier...you may eat into some of your profits, but being able to rinse and repeat with someone you trust is priceless!

Managing contractors and verifying quality of work/timelines can kill a deal.

Are their listings detailed with good-quality photos?

I tend to favor buying a few high quality properties in  coastal CA (Bay Area, LA, San Diego) over buying lots of less expensive properties in other states. 

As for the estimated income taxes, there’s no gain until I actually sell the house, at which point everything would be in COGS anyway—under your method or J Scott’s method—so I’ll know how much net income was generated and can easily estimate income taxes.

There are spreadsheets you can download that are in this forum that can help.Also checkout the enemy method for estimating rates and occupancy.