Getting to know the foreman could be tricky depending on how big the development is, as you could imagine he would generally be an extremely busy guy. His assistants / clerk of works might be worth talking too.
You could ring and ask about times for a site visit, depends on the building firm on how they handle this.
Personally if it was my site, I wouldn't let you near the place till it was time for you to prepare the snaglist. The logistics / health and safety of having tennants coming in for a visit would be difficult to say the least
To be honest being covered by HomeBond is a good start, this should protect you against any structural problems.
My spies tell me approx 50% of complaints to Homebond are about water leakage. So check things like windows / roofs / attics etc to make sure everything has been properly sealed.