Ok, well, he's going in with my Jullis in the morning

So, because he is in a critter keeper, water temps are different because I do not have a heater for him in there, how do I put my boy in the ten gallon? Do I just cup him and pour him in,letting him find a hiding spot right away? Or do I get a breeder net and let him get sit in there for a couple days,getting used to seeing his mates?( I do not think i could float the critter keeper lol!!!)
Oh, one more question, if he does not like the Julli's, what are the signs? How long do I wait before If I had to take him out if he does flare/chase?(a day ?)
Thanks all! Wish "Mint" and I luck!