I use wire solder also and I differentiate between the different ones by doing loops on one end: Hard solder - 3 loops, medium solder - 2 loops and super easy solder - 1 loop. No loops on my 20g sterling wire.
Just clip a small piece of each your not sure of and then place them side by side on a fire brick or solder pad, heat the both at the same time the one that melts first is the solder.
All my best .......... Danny
Yes, this works, but hard solder is close to the melting point of silver wire.