In my limited use of Maco 820, I've found it needs lots of filtration and seems to respond well to over-exposure. I have no idea where a red 25A filter fits into the scheme of things in regard to nm but it has an effect but not a huge one. I use some unexposed developed E6 as a filter to obtain 'wood' effect.
The exposure details of the attachments were...
film414-08 --> 1/30sec @ f16, no filter
film414-09 --> 1/4sec @ f16, 25A (red) filter
film414-10 --> 1sec @ f16, E6 filter