First, you need a single GC to give you a price on the entire job. You don't need to be chasing down all of these very busy trades who might fit your job in between the work they do for other GC's. Maybe.

$1000 down gets you on the schedule. That's it. It's a down payment for scheduling. No more.

If materials are involved, and you're dealing with small business individual contractors, they are all going to expect the materials to be paid for before any actual labor beyond demo starts. They are not a bank to float a project.

If you're dealing with a GC, they have greater cash flow capabilities, and usually structure the payouts a bit differently. It you are still going to have to figure that you will need to substantially pay for the materials up front.

And the percent of completion is usually followed. For some jobs, materials greatly outweigh the labor. Like cabinetry. For others, the labor greatly outweighs the materials. Like framing. When you're doing one big job with a GC , the jobs usually average out. That's why he can work with 1K at scheduling, 30% at job start, 30% at mid, 25% (or whatever the % is from downpayment) at 3/4 and 10% at end.

From the CSLB website:

Consumers also should be aware that their contractor cannot “front load”
the contract by asking for project funds in advance. That means a
person should never pay for work before it is completed, or for
materials before they are delivered to the property.

If you follow the CSLB guidelines of not paying for the materials until they are delivered to your property, then you may find it difficult to find a contractor. Why would a contractor take the risk of purchasing materials only to have the client possibly bail on them?

I have to pay for the materials upfront so my GC can order them but I pay for them as he needs them. Some of the materials are covered in the line items whereas others are a part of the contract (cost of sublayers of flooring) and I pay for those separately with a check to the vendor.

I pay for the work in progress stages stipulated in the contract.

I actually write different checks as I pay a check to the contractor for the labor and I write separate checks for the flooring materials (for example).

I am supplying a lot of the materials which are discretionary such as tiles, actual wood, faucets, fixtures, sinks etc. I pay my designer for those and write a check to her and she purchases them on my behalf.

I just checked my contract and I pay 50% of costs for materials upon order unless there is a shortened lead time for delivery - which effectively means I pay 100% for something in stock and 50% for items which have a delivery date in the future. This seems to be what is happening in terms of materials ordered through both the GC and my designer since so far everything I've ordered has been available for immediate delivery so I am paying 100% for the order. Honestly I am not stressing about the GC taking money for materials and disappearing as he has done work for people I know and done a lot of projects with my designer.

annied75, the risk goes both ways. The CSLB rules are there to protect consumers from unscrupulous contractors who might take their money without delivering a product, not the other way around. I agree it's problematic, but there are ways around it. For instance, payment for materials can be made upon delivery, or they can be paid for by the customer directly to the supplier at the time of order.