I would expect a payment after every major activity is complete. Demo, bathroom, exterior, kitchen, flooring, finish, closeout punchlist. Also an upfront cost to get started that way if I complete the bathroom and kitchen I can bill for both. Would like to bill out weekly or biweekly to keep cash flow going. Also this would break up the larger payments in your example. Also check with the general contractor on what he would like to see but keep it to payments once the activity is completed. This gives a reason to keep pushing the project forward to get the job done on time or earlier.
I would recommend paying your Contractor's on a Payment Schedule that is broken down by Category.
I typically create a detailed Scope of Work for the project that is broken down by categories (Demo, Electrical Rough-in, Plumbing Rough-in, Drywall, etc.). I then have the Contractor break down their pricing by these Categories which is used as a Payment Schedule to pay the Contractor.
The Contractor is then paid once the work is completed in each Category generally at the end of the week.
You also may want to consider holding back 5 to 10% retainage which will help keep the Contractor motivated to complete the work.
Here's a Payment Schedule Template in my fileplace: