Thanks for the responses, it is much appreciated. I will try to address everything in order.
The coax I used for my test is good; I check all my coax out on my analyzer before using it. I tested it on a 3 foot piece and a 50 foot piece into a dummy load. The power was significantly lower at the end of the 50 foot piece. The random length wire antenna only has a 6 inch piece of 174, so loss in coax, if using my desired configuration, will not be an issue. I only tested the 50 foot piece because I thought I might try using my buddistick (I did, with poor/no results) with the KX1 and just tried it for giggles.
By way of comparison, my 817ND puts out 5W on all bands through all lengths of coax, so it appears to be an issue with the KX1.
I bought the unit used and hoped that it would work ok out of the box so I could get some of the more difficult summits sooner, but I think it is going to the bench first.
I did give some consideration to propagation etc, I think the issue for me is I have refined my 817 setup and just wanted that same refinement out of gate with this. So I am lowering my expectations a bit and going forward from here.
I will also use those references for future propagation stuff.
I am going to research that W3EDP antenna, The only coax I use is a 6 inch piece to connect to the radio.
Only on 1 band did I get above 3 W, the rest were below more or less.
I am experimenting with the 16850 batteries. 3 of those give me approx. 11.5 volts and they are slightly larger than a AA battery. I have to use them more to see about longevity etc, but I think that will be a good fit for the KX1. They don’t give max power to the unit but I think what I am getting is a good compromise.
I did look into the MTR and that might be the way I end up going if this radio does not work out.
As for my 817 setup: for the hikes I do with it (8 miles round trip) I have no issues with the size/weight; that is why I have not scaled it down. I factor in an exercise component and don’t really mind it the way it is. In the event I decide this is the radio for the longer trips, I will definitely scale the stuff you mentioned (and other stuff) down.
As for the pack, everything you mentioned I have thought about, with one exception: the seat. I carry that leather because several of the summits I have done are super steep with rocky, moving ground. The second use for that leather is to save my pants/butt when I have to slide down rocky slides etc. It works really well for that and so I keep it in the pack.
Technically I did 4 summits that day, even though, to us it was one Friday night and 3 on Saturday. I used the KX1 on Friday, made only 4 contacts (thank goodness) and on Saturday, I ditched it on my first summit after making only 2 contacts (local) and half hour or more of trying other bands. I then switched to my 817 setup and I was back in business.
I am going to put the KX1 on the bench today and test it out completely and then get to building a better antenna system. I would really like to make a “long range” setup without having to take my other one apart.