There's no real limit in any sense of a clean line between OK and too much. It's more about sliding scales of benefits and drawbacks.

I won't go into the benefits, since you've already stated a preference for wider and I'll respect that. The drawbacks are reduced frame clearance, meaning less margin should the wheel break a spoke or get bent in a minor crash. My rule here, is that I want at least as much as I'd gain by releasing the brake, more if possible. While you're at it, be sure to note the vertical clearance under the brake caliper since this often becomes the first limiting factor.

The other drawback is much more subjective. It's the floppiness that wider tires on narrow rims have and how that effects handling, especially at lower pressures. To understand this effect imagine holding a water balloon between two fingers. The higher (closer to the diameter) you hold it, the more stable against side forces. A tire that's very wide compared to the rim is like holding that balloon with your fingers close together near the bottom and will feel squirrelly. But this is a question of degree and what I may feel is terribly unprecise handling, may be perfectly fine to someone else.

So go as wide as you want, subject to clearance issues, then if the handling isn't satisfactory, back down until you're OK with it.

Lastly, is the issue of hoop stress, or how hard the tire tugs outward on the rim flanges. This is proportional to the product of tire width and pressure. Rim makers design around expectations tire width and operating pressures with the assumption that wider tires will be run at lower pressure. However many wider tires have higher pressure ratings these days, and so can produce greater rim stress. This probably won't an issue on a new rim, but will determine the maximum wear limit before failure. Something to think about on a bike where rim wear is already an issue.