Hi Growler and Sugarcatmom,
A bit of an update.
This is getting curious. Or perhaps I am really at clutching at straws time. In the last 24 hours there has been a change. Is it significant or just something transiently positive? I do not know.
I believe I mentioned that I was feeding the two cats Nature's Variety canned and I have been using this food in various flavours for about the last 4 months. I always look at the nutrient content and for nature's variety Prairie/Homestyle (they do not like the Instinct canned) the figures are pretty good. I have always chosen lower phosphorus canned food for my kitties and these are not bad at all at around 1% on a DM basis. Sodium was not that high either although higher than some foods at about 0.6% on a DM basis.
http://www.naturesvariety.com/prairie_cat_can
Well, I had run out of the Nature's Variety and with all the rushing on Tuesday I went to the closest pet store which normally has little super premium and I bought 4 cans of the new Hill's Culinary Creations canned. Carbs too high for a canned food but sodium I noticed (on checking hillspet.com) was about 40% less than Nature's Variety.
Anyhow, Yesterday morning I continued my measuring of water consumption (having a control bowl as well for evaporation) and even though I cannot be exactly precise I do know who drinks from which bowls (3 of them). This morning checking water consumption I work out that Samantha must have drunk less than 100ccs of water in the 24 hour period. The litter box clumps are also markedly less than on some days.
This was all intriguing me and I decided that I would see if I could get a free catch sample this morning. I know it was not the first of the am (since midnight last night) but I managed to get one. A friend of mine has taken this to the vet now. All I am looking for at the moment is USG but what was somewhat heartening is that the colour was more yellow. I feel there is a good possibility that this is better than what I got on Tuesday - 1.009 - but I doubt it is at say 1.030. Just taking small baby steps now and perhaps this whole thing is just a red herring.
Edit: When I say "red herring" I really intend to say that all this reduced water consumption etc is a false hope on my part that matters are somehow materially improving.