Bidet seat choices and water supply

Hi, newbie here...

Remodeling one of our bathrooms and with new toilet, would like to install a bidet seat. The choice of toilets is Kohler Santa Rosa or Toto MS854114S, just because I already bought them.
I also already purchased (but can return it) a Swash 900 Electric Bidet from Home Depot. Also looking at Bio Bidet USPA 6800 as an option.
So far it looks like there is not enough distance between the mounting holes on the Santa Rosa for the installation of the Swash, and I doubt there will be enough for the USPA. That probably leaves me with Toto - not that I am complaining
Comparing the two bidet seat choices I like the fact that Swash has stainless steel nozzles, but it comes short IMO in option choices in comparison to USPA. The later also has rear mounted cord compare to the Swash's side mount (that I happen to hate). Unfortunately both of them have a side mounting water supply, but i guess that fact is unavoidable, at least until the toilet manufacturers can come up and agree on the universal bottom mount placement for the water supply.
I am also debating if there will be any benefit of running a 1/2" hot water supply to the toilet location and premixing it before the inlet to the bidet, since I have all drywall out. I know nothing about how they work, so it could be more harm then good, maybe someone here knows for sure?
Thanks in advance,

If you like the MS854114S Original Ultramax, you would likely very much like the Ultramax II, which looks a smidge more modern and has a dual-cyclone flush, an ADA height bowl, and CEFIONTECT all standard. It's MS604114CEFG -- look it up -- and you will find that it is actually comparable in price even though it has all these extras.

The Swash should fit the Ultramax and Ultramax II. But get some input on here from folks who have actually used the various bidet seats. Terry sells a fair number of them and is a great resource about them.

Thanks for the quick reply,
That's the thing, I actually already have both toilets (for two different bathrooms) and not planing on getting another one
Found this option at HD http://www.homedepot.com/p/t/100670862?storeId=10051&langId=-1&catalogId=10053&productId=100670862&R=100670862#.UqFekuLn8So
It looks appealing to me because I can bring in that hot water line and has no possibly costly electronics.