When I use 10 ohm resistors, i notice that my blue and green leds, even though bright get extremely hot, like, hot enough to melt its solder off after a while, not to mention the fact they dont last long
And also, dont use red leds with 10 ohms, they just blow up, i had to learn the hard way lol
I use 50 ohms myself, and sometimes 100 ohms, they may not be as bright (not that much dimmer IMO)
but they dont go way too hot and last longer
Im not so familiar with silver based solder, but id just say, if u have any flux, just use that in conjuction with solder