@niranjan
I am glad that my information is useful for you. I did forget to mention that I do, indeed add Tween-20 to my coating solution. I add 1 drop of a 10% per 2 mL of coating mixture. I now do this for all papers as I have never found that it hurts but it sometimes helps.
I think that brushing on the solution is much more satisfactory than a coating rod. The brush really allows one to work the solution into the paper. In my view the only reason to use a coating rod is to save on expensive precious metals which, in my view is not at all an issue with cyanotype.
I am no expert on paper or sizing, but my understanding of the difference between watercolor and printmaking papers is the same as yours. To be honest, I can say that I did not really make a conscience decision between watercolor and printmaking papers, I just tried what I had in my stock. I also use both watercolor and printmaking papers to make black and white inkjet prints using both OEM Epson inks and Piezography K6 inks so I had them around.
I have also used a number of hot press watercolor papers as well, but I am slowly coming around to the view that they need pre-acidification to get consistent results. (I know that this is not news to many folks, but I like to make my own conclusions!) This is also true for many printmaking papers as well. One of my favorite papers for inkjet prints is Stonehenge Warm and initially I thought that I could make good cyanotypes on it without pre-treatment, but I could not do it consistently.
I am currently working on a method for pre-treating papers with fairly dilute (~ 0.1 M) HCl and using the solution only once. I know that many folks use sulfamic acid or citric acid, but HCl is dirt cheap and easily available as muriatic acid in building supply stores. I bought a gallon of 31% HCl (about 10 M) for $6.00. Thus, as long as one doesn't mind having to work with concentrated acid it seems a good approach. (Remember... I am a retired chemist, so I'm used to handling concentrated but I understand that many folks are hesitant.)
Regards,
Having said all of that, I may be slowly deciding that the extra steps involved in pre-treating may not be worth the effort if there are nice papers that work without pre-treatment. The two Fabriano papers seem to work this way thus far. I have also recently ordered some of the unbuffered papers designed for alt process printing to see how much better they are in my own hands. (I am also thinking about trying Ziatypes next and this is much more of an issue there I believe.) In addition to their expense, I find the selection of sizes that these papers are available in to be troublesome.