Polymer for diy solar eclipse filter?

Recently bought a Nikon d3300 to get back into photography (took classes in hs but never owned my own camera, I know how to work and take care of a DSLR). There's a solar eclipse this weekend and I purchased a polymer sheet to create a filter (link below). I wanted to make sure that I'm not damaging the light sensor inside the camera. Would having the f/ stop or ISO higher/ wider appature cause damage even with using this filter?

I typically do not ask questions because most the time there would be a comprehensive article regarding this, but I was unable to locate this information online. Also, me owning my first dslr /would be my first attempt at taking photos of the sun I would like to persevere the quality of this camera as long as possible. Any feedback/ personal experience would be great and thank you for helping me in advance!

eBay link for polymer sheet I purchased:
http://m.ebay.com/...mwBanner=1

If this is real Thousand Oaks Optical filter material, then it will be safe for viewing with your eyes and camera.

Since it's an ebay purchase, the seller is new, doesn't have any feedback, and is from New York, I would exercise a bit of caution and verify that the film does what it's supposed to do. The price is also very good, but he may have ordered a roll and cut it to size.

First test is hold it up to a strong light, like a 100 watt bulb and be sure you can barely see the bulb through the material and there are no pin-holes in the material. If you find pin holes, it may be counterfeit as black polymer filters don't have pin holes. Next, try it out on the sun, briefly at first.

You can easily make a holder for the filter material out of cardboard that slips over your lens.

For lens selection, you should be using a minimum of 300mm focal length. The image will be small if you use anything less. The sun and moon disk fills about 1/3 of the frame height using a 500mm focal length on an APS-C sized sensor such as yours.

Top my mind, in photographing a solar eclipse you are "chasing darkness" in the exposure level, thus you will need lowest possible ISO and small f-stop, (e, g.f16) and high shutter speed (1/1000th, 1/2000th?) when photographing the Sun, even with any form of and filter, whether bought as such or home-made.

I hope you have a god long tele or zoom lens available. Even a 300mm will show the Sun fairly small.