Question for Experienced Developers/Analysts

[Dion Huey]

Hello, Bigger Pockets Community!

I am working on a mock real estate development project submission, and I am looking for some general rules of thumb on how best to estimate the following:

1.  Demolition, site preparation time and costs.  The existing site is a 60,000 square foot, 20-story building on Hong Kong Island.

2.  Construction Length of Time.  We are planning construction of two 24-story towers with a total construction floor area of 70,000 square feet over a two year period.  I looked into other projects recently built by a developer we would like to recommend and determined they typically complete projects of similar size and type inside of two years.

I understand many variables can affect both demolition and construction time, but I am only looking for a general rule I could apply in the absence of reliably sourced data.

Thanks for your time!