Ive been using the Pilot Frixion pens for quite awhile now. They work great, are affordable and you can get various colors. You can also find them at places like Target.
I have an air soluble marker, the lines fade pretty quickly especially if there is hot/humid climate. I found they fade also with contact with the skin and some warm water. They last between 4-5H to 24-26H depending on a lot of things. For the water soluble one I cant recommend any but if you dont want to regrid the project everyday I would use the Bohin mechanical pencil that comes in very different colors, I prefer the white and green leds.
I dont use air soluble pens. I grid when I have my project on stand so it usually work for weeks I think Ill get annoyed pretty fast if my grid will disappear on me & instead of stitching Ill have to re-grid. So I use water soluble & uron soluble which stay on fabric for years if I need them to
i alwaxs use blue (only blue - not any other color) water soluble pens and never had any issues with it. I always wash my finished projects, so i don´t care about the water pens
chekccard