No, do NOT use saline solution with colloidal/ionic silver. Silver plus salt is not a good combination - unless you want to join the Smurffs. Actually, it would take a lot of repeated use of silver plus salt but that is what happened with the infamous blue man "Papa Smurff" Karason, who got paraded all over the country as an example of silver turning people blue - he made his own colloidal silver with tap water, added salt to it and drank over a quart a day for months on end. He also applied it to his face.
No need to dilute it at all. Silver solution by itself works great. Adding 1 part lobelia extract and 1 part mullein extract to 5 parts silver solution works even better.