I am a selling agent for a very nice subdivision in my community and, as such, sell pre-built and pre-sold homes. I use our standard State contract to submit the offer and attach a Builders' Addendum to it that clearly details all of the construction specifics. This works well for us!
I have sold and worked in new homes for several different builder. Some used their own and some had me use the state forms. The ones I really liked were the ones where the builder had an onsite agent and I could just sit back and watch.
New construction uses their own contracts. make sure you are present for the initial meetings so the company can honor your agreement. if you can not make it call in advance and let them know you have clients coming in.
You need to speak to the builder. If this is not just a single home someone is building but a big developer you must get informed about commission, concessions, etc. I have received as much as 7% on new construction from the developer and have negotiated huge credits for my client.
Usually "new Construction" has their "own" disclosures and contracts.I would write up a standard offer and go with the client to the office to present the offer and discuss terms with the Realtor of the builder.Make sure you get all the upgrades and benefits you want for your client at that time.
Each State may be different but here in Texas you do not use the standard contract. New builds have much more in their contracts and typically extend 50 pages or more. What advice does your broker have?