Young forward Maris, 19, switched from the League One outfit to Nethermoor in time to make his National League debut in the 1-1 draw with Southport on Tuesday night, with Lions chief Bower pleased with his input.
Maris, who can either play up front or as an attacking midfielder, has featured twice at first-team level for the Reds, making his debut from the bench in the game at Bradford City in late April.
Maris, who joined Barnsley at under-15 level, then made his full bow in the Reds’ 5-0 victory over Rochdale on the final day of last season at Oakwell.
The teenager also spent a loan spell at Nuneaton last season which Bower believes will serve him well for his time at Guiseley.
Bower said: “George is highly-rated at Barnsley and was involved in a lot of their first-team games in pre-season.
“The important thing for us is that we added someone who is experienced at Conference or Football League level before and George had a spell at Nuneaton last year and that will have done him the world of good.
“George played very well there and he only came in here on Tuesday morning and then came straight into the side on Tuesday night and really grew into the game as the game went on. I am sure he can do well here.”
Meanwhile, Bower admits to a level of frustration after his side were pegged back by a late leveller on Tuesday.
He said: “It felt like a defeat really – conceding so late on when we have the chances to really put the game to bed.
“It was disappointing really. We played well enough throughout to win the game, without setting the world on fire.
“We couldn’t hold out in the end, although they didn’t look like scoring.
“They didn’t really have a chance; it was just a shot from range really.”