Josh (Q), while there are quite a few ovens out there that have 500 as the peak temp on the dial, in my experience, usually these ovens can hit at least 525. You happen to belong to an especially unlucky group of oven owners who's ovens fall short of the 500 on the dial. Had I been aware of this prior to your steel purchase, I definitely would have dissuaded you from buying steel, because, at those temps, there's not much you can do.
Since it's a little late for that, and steel is what you have to work with, here's what I'd do...
Place your steel in a shelf about 6" from the broiler. Cover almost the entire rest of that shelf with either aluminum foil (good) or a combination of aluminum foil and quarry tiles (better). You want to leave about a 1/4" gap on one side for the gases to flow through to maintain proper combustion. The position of the gap will correspond to where your temperature probe is located in the top of the oven. If the probe is on the left, put the gap on the right. If it's on the right, then gap left. If the probe is in the middle, it doesn't really matter that much.
The probe is what turns your oven off when it hits the temp on the dial. By covering almost the entire shelf, you're isolating the heat in the bottom of the oven, and delaying the time it takes for the probe in the top to reach it's max temp and shut the oven down.
This will give you a fast bake. The catch, though, is that it will most likely be only one or two fast bakes, because the heat, over time, will eventually flow to the top of the oven and even out, and, you'll be using the broiler during the bake and heating the upper chamber as well. You're basically creating an imbalanced heat scenario, that, over time, will balance.
It's going to take a little trial and error to see how long of a pre-heat will give you the hottest steel. I would turn the oven on full blast and do IR readings of the top and the bottom of the steel every 20 minutes (skipping the first 20). Try to take the readings quickly and in a similar fashion so that the heat loss is both minimal and consistent.
Covering the shelf should trap enough heat in the bottom chamber that, for a period, your steel should spike to at least 525, which is the magic temp for fast NY style bakes.