Negative Carrier Glass, Anti-Newton or not?

Hello Everyone,
I need to find replacement glass for my father's old enlarger. The negative carrier of his Durst 609 has some cracked glass. This is a very old enlarger but everything else seems fine. The negative carrier seems to have plain glass on both sides. Would I benefit from using anti-newton glass or would that be a mistake? I ask because I figured that it would be a good thing, like an upgrade..but would hate to have the glass cut for the carrier only to find that it produced ill effects. Any advice would be great. The carrier is a Durst ADANEV 72 if anyone is interested.

Thanks so much.

Anti-Newton on the top and regular glass on the bottom is a reasonable combination.
You can get the glass here: http://www.fpointinc.com/glass.htm

Enlarger type makes no difference. Plain glass against base side of film will sooner or later give random newton rings. I have taken those negs and rewashed them and the symptoms are still there. Test negs dried with a hair dryer still show them.

The only solution is AN glass on top, plain on bottom.

I replaced the glass in my carrier with AN glass from Focal Point. Very satisfied customer.

Thanks everyone,

I've been discussing the glass with Mike at Focal Point. He has been EXTREMELY helpful and very easy to deal with. I wanted to post a portion of his email for anyone interested. This is very similar info to what Michael R 1974 replied with. Same person???? Anyway, thanks everyone so much for the kind help. I really appreciate it. I'm going to go with what Mike (Focal Point Mike) suggests. Since I have a condenser enlarger (dual-condenser, according to the manual), I'm going to start with regular glass. If I have any problems I'll get some of the AN glass for the top piece. This is my first time using an enlarger and I'm sure for a while I'll just be thrilled to get any image at all (everyone reading this can relate I'm pretty sure). What started out less than a year ago as me borrowing my dad's Mamiya C33 on a whim has turned into a full fledged obsession. I would have NEVER guessed.

Sincerely
Paul Cretini

Here's the excerpt from Focal Point Mike's email:
"AN glass works best with enlargers with diffusion light sources. These are the enlarger heads that have a diffusion box and diffuser directly above the negative carrier. A condenser light source will have a large lens just above the negative carrier. These create a very sharp direct light source. Since the light produced by this head is so direct there is a chance that the texture of AN glass could show in a print. It would show up in broad even areas like cloudless skies or paper backdrops.
So if you are using a condenser light source I suggest beginning with your two pieces of clear glass and study your prints for signs of rings. They will show up even in black and white images in various shades of grey. If you don’t get rings then there is sense in getting AN glass. If you see rings you and want to use AN glass you can place a piece of white Plexiglas above the negative carrier to help reduce the possibility of seeing the AN texture on prints.
If you have a diffusion head I’d probably use the bottom piece of clear and top AN glass just to make sure that you don’t have to worry about any Newton rings. The cost of the glass will eventually be made up in paper savings."