Right I'm not exactly upon this but I think the following is true;
The droplet volume has no effect on the contact angle go ahead with the larger volume droplet (try on a less hydrophobic surface, with a small drop then a big one measure contact angles compare+tell me if I'm wrong!)
The...
Polyvinyl alcohol would give a reinforcing effect while dry and a controlled solubility on entering water. ISP ltd should be able to help, they do loads of varyingly soluble polymers like polyvinylpyrollidone that would allow you to fine tune the solubility. They're also very safe biologically...
