Due diligence period for spec home?

[Jason T.]

Looking for some advice on how spec home offers are typically structured.  I'm in North Carolina and looking to buy a spec home that should be ready in about 4 months.   I have a few questions and hoping that some of the more experienced folks here on BP can offer some advice:

1) On a typical purchase, i'd normally have a 15 day due diligence period and then the Earnest Money Deposit becomes non-refundable.   But if the home isn't ready for a few months, how can I do an inspection and release all contingencies?  Does the DD period normally get extended?

2) Also, how do I make sure that the builder doesn't skimp out of quality and finishings once he gets an offer locked up?  I assume I can have him commit to some stuff (fixtures, appliances, etc), but there's no way I can identify everything (nor would I want to be spending time on checking every single thing).  Is this just a question of good faith and trust? 

3) Any other lessons learned or suggestions?

Thanks in advance!