The two new recruits are part of the squad currently in Portugal as part of the club's pre-season preparations.
And former Blackpool boss Holloway feels the trip will be valuable for integrating both players into the first-team squad.
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"They've been excellent," he told the club's official website. "This will help them get to know people, eating together, training together, staying together.
"It's only been five or six days, but that's been important for me - that camaraderie and getting some decent training under their belt.
"So many players want to come here, they want to come to this level, they want to come to London.
"We'll try and have a much stronger squad because we'll need it to compete with these clubs that have all sorts of money and resources.
"People like Jerome and Gayley typify what Palace are all about really, with young people and hungry people.
"Hopefully our fans will get to love them and sing songs about them."