Has anyone here built a block of units?

Hi all
further to my thread earlier that we had bought another property....has anyone here have any experience in building a block of units. this has been our long term plan with these houses for the last few years that we have been buying them. We have just been biding our time waiting as they come on the market but we are now well and truly within reach of achieving the requisite blocks. Under the current zoning we can build units up to 4 stories high (so quite a lot of units)

We estimate that we will have the 30% deposit required in about 2 years and so are starting our research now.

any help would be much appreciated.