I've done many a cycle with fish, in my freshwater tanks. However, I'm also more than willing to do ammo and nitrite tests every day for 4-6 weeks, and follow that test with a water change if needed (and for the first few weeks, its needed about every day, and then every other day for another couple weeks). That's the only way to humanely cycle with fish. Since I have planted freshwater tanks, the ammonia never builds up very high.
However in my salt tank, it's fishless cycle the whole way.
If you're going to Europe tomorrow, expect to come home to dead fish and a funky smelling tank. 3lbs of LR
isn't enough of a bio filter, so unless you had an existing, cycled filter that you put on this tank, the livestock is probably doomed.
I'm not trying to chastise you...you're new...you don't know any better. I'm just being honest, and don't want you to expect to come back from abroad to a healthy tank with live fish.
Have fun on your trip! Don't stress on the fish. When you get home, we'll be here and more than willing to help you do everything the 'right' way.