3x or 4x Townhouse?

I have a site which is 800m2.

And my options are: to either build 3x large 28sq townhouses or 4x townhouse (2x 17sq townhouses and 2x 21sq townhouses).

Paid $1.2 Mill for the site a corner lot in Essendon.

I want to keep the first townhouse and sell the remaining townhouses.

I know if I build 3x large townhouses they will sell for just over $1mill (3x $1mill = $3mill)

compared to the

4x townhouses which would in the range of ($680k for the 17sq’s = $1.36mill)
($750k for the 21sq townhouses = $1.5mill) = $2.86mill

Cost of construction would be almost $1mill for complete completion for either 4x townhouses or 3x large townhouses.

All townhouses would be detached.

The land was purchased under a trust.

How much tax would I need to pay if I decide to sell 3x or 2x townhouses (Note I would keep the 1st townhouse for myself)

Would it be wiser to sell off the plan and are there any tax benefits by doing this.

So if I build 3x townhouses and sell 2x townhouses how much tax would I be required to pay (A builder would be building so I would have no part in the construction of the townhouses)

Also if I was to build 4x townhouses and keep the 1st one and sell the remaining 3x townhouses what tax implications would I encounter and what would be the best path to take.

I want to use the funds from the sale to fund another project.

If someone could shed some light on this it would be of great help.
i would go with the four units , note the rent in the burb, your building in , also rent on 1m + homes get no where the return smaller ones do, why?????
so value the rents in comparable units , and knowing the rental market is geting tighter , they will all be leased , you should do these sums first before you choose to sell them , you might find a short fall of 1k a month, by the time they are built and rented, so cross that bridge when it comes.
Drawing down the equity not an option? The depreciation on the new places would be worth hanging onto for a few years wouldnt it?