Conspicuous means I shouldn't have to go searching for it. So I don't. When you call, ask, check every entrance, or go digging into policy manuals, you are searching, meaning if you are "mucking" yourself, as it is obviously not conspicuous.
It also means you shouldn't call ahead, or ask them what their policy is. Part of carrying concealed is "out of sight, out of mind." When you put the idea in their head, you are often the inspiration for them creating a policy. Conspicuous means conspicuous, and concealed means concealed. Stop searching for signs and obscure policy, and stop announcing to every business owner or manager that your carrying. I have no idea what motivates either action.
If you want to see uniform signage passed, contact the BoD of the NFOA and the NFOA-PAF, and ask what you can do to help 1.) get the right people in the right places, 2.) motivate those people to present and push NFOA backed bills, and 2.) get those other people to support NFOA backed bills.
Uniform signage should be easy compared the all the pipe dream bills, and with any luck, could make a whole slew of non-carry places now open to business for 2A supporters like you.