Considering Repowering Again

I'm repowering for the reasons mentioned. Difficulty in finding parts and service, especially for the DDEC electronics. I like the idea of getting rid of the remote trolling valve actuators and cables and having a simple plug and play. I hate that the DDEC stuff is all 12v and the starting /charging is 24v. This makes me have batteries and chargers just for the 12v DDEC. More stuff I can get rid of. The Detriot's have tons of hoses and hose clamps. Everything is moved around the engines in hoses. I have had several hose clamps break causing problems. We went through and changed all the hoses and clamps and have had failures of new clamps (yes, the expensive t-bolt style). I have an opportunity to get a good deal on the CAT's and I have some specific business reasons that make the timing right to do this now. I'm not doing this for the sole purpose of fuel savings. That wouldn't remotely pencil out. I'm also doing this now because the true master craftsman that does all the work on the boat is talking about retiring next year. I want to get this done while he is available to lead the effort. I need to replace my gens too so much easier while the engine room is open. There isn't any one resaon, just a lot of little ones.
I thought about selling the boat and getting something that already has C18s or C32s. I'm going to be about the same, maybe aa little less by repowering but I'll have brand new engines and gears. Further, with a newer boat I would have to start all over again outfitting it for Alaska. We have spent 7 years and tons of money and effort getting this boat where it is. I don't want to do that over again.

I'm partial to Northern Lights. I've heard nothing but good things about them. My current set-up is a 20kw and an 8 kw. The 8kw meets most of the demand and is what I run all day. I only run the 20kw if I have high loads like the washer/dryer, water maker , A/C, etc.

What I would really like is to install 2(ea) of the NL 9kw units and be able to run either one independent for day use then be able to parallel both during occasional peak loads. I will talk to NL to see if they can offer this. I don't need any type of power management or auto start/parallel feature. A manual switch to select either gen or both would be perfect if possible.

That's a perspective on 1(ea) 20kw and 1(ea) 9 kw that I hadn't considered. I will have to give this some more thought. I don't have room for 2(ea) 20 kw and besides most of the time it would be terribly underloaded. The 20kw will get almost no hours. But at least I can get a 9kw out if I had to replace it at some future point. Going back with a 20kw and a 9kw would be easier since that's what I have now.

I spoke to soon on going with the 1.525:1 gear ratio. Upon closer investigation discovered the existing gears are 1.66:1 (not 1.60 as thought). So now likely going to go up to 1.757:1 as this is closer to existing then going down to 1.525:1. CAT also tells me that slower shaft speed with more prop pitch is preferred vs higher shaft speed and less pitch. So the 1.757:1 likely works best. This is also a more common ratio than the 1.525 so hopefully lead time improves on the gears.

Can I not simply add some pitch to existing props? It seems like not much change from 1.66 to 1.757 but maybe I'm underestimating. No, I'm not planning to change shaft size.

Thanks for all the great input.