Sometimes the contractor will put a % on the top of the materials to source it.2) what's your range for remodeling a bathroom?

Read as much material as possible and go to some local RE meet ups.

You are reading the right material already.

Real material cash flow is basically 50% of your net income.Cash flow is a metric that requires a debt ratio.

I stick with the main OTAs and have added GVR since I believe that one could materialize but trying to get direct bookings is also difficult.  

Yes, you personally aren't living there, but with high crime comes unqualified tenants and high maintenance costs (stolen materials, broken windows, etc.).

I don't work on houses, but I have to use B and A-basis values for material strength which in effect means the real material will end up being 20%+ stronger (depend on the material).  

I would need to know more specs on the house but with material shortages It's difficult to say how much to budget. 80K-120K for full gut perhaps but unsure with lumber beings so expensive and shortages.I would plan 9 months of vacancy between the pain you will endure pulling permits & having your contractors show up everyday to complete the work & then final inspections to get a CO. 

Spend more than half of your total working hours in an RE business in which you materially participate.2.

However, I do not know who this could be beyond a property manager which would not work in my case since I am looking to self manage for both tax (material participation in STR loophole) and profitability reasons.