What size hoses are you running for your nitrous? If you have the 1/8" tube, maybe your getting to the limit of what it can flow with the 24 jet, and now you went bigger with both, so the nitrous can only flow so much, but the fuel can still flow more if you understand what i'm saying. LOL. Especially if you have compression fittings, they can squash the hose some too which will make the i.d. of the hose smaller and then they can only flow so much. Obviously if the i.d. of the hose is smaller than the hole in the jet, it won't flow what the jet is meant to flow, the i.d. of the tube will be the limiting factor. The other thing that comes to mind is bottle pressure. If your bottle pressure isn't high enough, it'll go rich too, especially when you get low on juice. I'm no expert by any means, but just some food for thought.