OP, I've asked similar questions before and never really gotten what I consider to be fantastic answers.
I think what it comes down to is a tradeoff between the costs and benefits. My only thoughts are to look at everything and consider future years too.
By everything, I mean there are essentially a bunch of different taxes that phase in and out at different incomes. Mostly we report and pay all these different taxes on our federal and state income tax returns. But I have kids in college and there is effectively an additional tax system called financial aid that is based on federal AGI and other things.
Back to federal and state income taxes, what you'll find with such a low income is that there are tax credits that phase in and out at various levels - ACA premium tax credits are the most often discussed today, but there is also ACA cost sharing reductions, earned income credits, retirement savings tax credits, education credits, etc.
The easiest thing I've found to do is sit down with an online tax program (I like TaxAct for this), and plug in your base case and jot down how much you'd owe in federal and state taxes. Then increase your conversion amount by $5K and see what it does to your taxes. Then increase it by $5K again, and jot those numbers down. Then if you plot those numbers on a X-Y graph (total taxes paid vs. income), you'll see if there are any bumps or slopes that are significant. You can also decide - like I almost have - that paying X% of your income in taxes is OK, but not more. Then you can pick that point on the graph and use it.
Usually I will find the broad strokes with a $5K resolution, then once I pick an area I'll go back in and do $1K intervals. You can also look at the return itself and see, if there are any discontinuities, why they happen, which may lead you to make additional tweaks.
Often, as in the case of conversions, these steps need to be taken before the end of the year. I usually start my tax planning around 12/1.