[Plugin: NextGEN Gallery] NextGen Gallery Custom Carousel Template not working

Hi all,
I have NextGen installed and want to use the carousel template, but needed to modify the template (gallery-carousel.php) to suit my needs. I’ve done this successfully and works fine. Clicking on my thumbnails triggers the large image to change accordingly.

So here’s the problem: I’m concerned that if the client upgrades, the changes I made to the gallery-carousel.php template will be overwritten. Because of this, I decided to take the changes I made and put them into a copy of the page (saved as gallery-carousel-copy.php), using it as a custom nextgen template. On the page with the short code, I call to the gallery with this code:

[nggallery id=1 template=carousel-copy]

Unfortunately, I’m doing something wrong because although the first page shows up as it should (large image, thumbnails), the minute I click on one of the thumbnails to navigate, I get an error that states:

“Rendering of template imagebrowser-carousel-copy.php failed”

I’m not sure why it’s referencing an imagebrowser file, and one that doesn’t even exist. So then I thought, maybe I need to also make a copy of the imagebrowser.php file and save it as imagebrowser-carousel-copy.php. (attempting to shoot a moving target here…) When I do this and try clicking the thumbnails again, I no longer get the error, but it instead switches to the image browser mode, where the page changes, the thumbnails no longer show and I get previous and next buttons on the bottom. I don’t want it to switch to image browser mode.

I’ve quickly realized this is way over my head.

Can anyone explain to me:
1) Do I even need to worry about my modified gallery-carousel.php getting overwritten with an upgrade?

or

2) Can someone walk me through the steps of creating a custom nextgen template successfully?

or

3) has anyone else come into this problem and if so, do you have a solution to this?

Thanks for your help.