Johnny,
On a previous Collimation thread, Malcolm gave the link to a very useful article on collimating a Newtonian reflector at
http://www.astro-baby.com/collimatio...on%20guide.htm
I hope you have had a look at it in all your research.
If you want a 35mm film canister, go into your local Chemist shop and ask if they have any empty ones spare from the days when lots of people got films developed. And when you do get one, paint the inside of the cap white. This will make the reflection of the centre hole stand out more.
And re Moon Filters - some give the moon a green tinge. I have and prefer a Neutral Density filter. It cuts down the glare without changing the colour.