Homebrew PCBs

Hi,

while we are at the subject, i want to buy some paste for this  
application. I have tried it with old (lead) paste and it works well, but  
i don't feel comfortable with the disposal problem (as some of the paste  
is washed off). Also i hope for a nicer finish with tin paste.

I have the choice of:

ROSOL 1S S-Sn96,Ag4 250g 15eur

ROSOL 3 S-Sn97,Cu3 250g 10eur

Now what is the difference between paste with copper and paste with  
silver? I don't really mind the price since it will go a long way.
I remember some leadfree solder (wire) has silver in it too?

Anyone doing the tinning, what paste is yours?

Thanks!

ST