As for adding red sensitivity, a good aggregating red sensitizer is available from H. W. Sands Corp. in Titusville Fla. This dye was discussed completely in another thread. It is a Green sensitizer on Bromide and Chloride emulsions and a Red sensitizer on Br/I emulsions due to "J" aggregation. It is used in Kodachrome film AAMOF. I have 0.9 grams of it here. I used 100 mg already. This dye runs about $300 / gram right now IIRC.
Do you know the name of this dye? I would like to try it.
There is almost a full thread on the dye in this same forum under another thread. Since there is some controversy over the exact number on the manufacturers web site, I don't want to rehash or repeat it here, but rather you should look at the other thread. I believe that wildbillbugman was the main contributor. I'm sorry, but I do not save URLs.