I don't really ever go over 45 lpi on paper and 22.5 degrees is pretty safe most of the time. Realistically if you wanted you could go 55 to 65 lpi halftone on 305 given your using a nice mesh like murakami s-mesh (the threads are really skinny but strong). Good rule of thumb is mesh count divided by 4.5 but thats the tail end of what the mesh might hold, I would never go that far, always safer to go under. Also, photoshop outputs a terrible halftone dot or ellipse, a nice RIP would be the best, but if you don't have the funds get ghostscript it's a free RIP and you can export photoshop files as .dcs or even single files to illustrator and setup your output in the print settings and save as a pdf then print out of ghostscript to your printer.
I would run that at 55-60 lpi on a similar mesh to what you're using, depending on what I was printing on. What are you printing on by the way? But the higher the better if you and your substrate can hold it without making a smeared out mess.
You can get a decent halftone out of PS via bitmap conversion. Do two things:
1. Get to know the Curves tool. This is going to take the place of dot gain linearization for you. A gentle "S" shape is a good start point.
2. Set the ppi for the file as high as your rig can handle, set it the same in the bitmap conversion.
Should make reasonably clean dots. My RIP doesn't really make out of this world dots anyhow so don't stress not having one for the one color stuff. A RIP winds up being more of a workflow thing, saves massive time and gives you more control and consistency if you are running a lot of seps. Also remember you can save this as a tiff and place it back into illustrator if there's vector work that needs to happen.