Budget Camera Testing: Establishing a Visual Language Without a $10k Rental?

Hey everyone,

I'm a camera operator, Tyler, and I'm currently prepping for a narrative short where I'll be stepping into the DP role. The budget is, let's just say, 'focused.' We'll likely be shooting on an FX9 or a C70, with a basic set of primes and a couple of amaran 150c's. I'm really trying to establish a strong visual language, especially with color and falloff to give the film some character, but all the advice I'm seeing for proper camera testing talks about $10k+ rental packages and full days at a studio.

Without that kind of budget for elaborate tests, how do you all approach effectively testing a camera, lenses, and lighting to figure out the look? I've been doing some quick tests with my own a7S III and a couple of inexpensive lights, just trying to feel out rough exposures and color, but it feels so far removed from what we'll actually be using. I can probably swing a half-day with the actual rental gear, but that's it.

Any practical tips for tight-budget DPs trying to nail a distinct visual style through testing?