Relay vs christmas lights

@Paul_B : I really don't know what a snubber is...

However, I think I've learned some things from this thread (thanks again to you all):

  1. I have to insert a decoupling ceramic capacitor (100nF) for every shift register close to the vcc of the IC; and I have to leave where it is the electrolytic 10uF capacitor

  2. to avoid ssr leakage that lights on the led strip I have two chance:
    a) insert a resistor between the AC outputs (correct? which kind?) in parallel with the led strip
    b) choose a led strip that requires more corrent draw

Correct?
Thanks for your patience.
Ciao,
Giuseppe