Since you are going to purchase a KX3 anyway, why don't you consider just buying it instead of the other two and use it as your base and portable? The money that you save could be used to buy an amplifier for the KX3 and a 2 meter option will be available for it soon. I have both a TS-480SAT and a KX3. I love the 480 and think it's a great unit, but I'm having so much fun using the KX3 that I find myself using it in my shack much more than the 480. I'm finding operating QRP is a lot of fun. The KX3 is very easy to learn, plus you have the fantastic Elecraft customer support. Just wanted to throw that idea out there.
I did that very thing, just today! Being brand new, I was trying to take some advice around here, but most people were steering me away from the KX3 for one reason or another. In the end, it makes much more sense for me, since I need a rig I can use for a base, and for field. I'm also interested in data modes too, and SDR control too. I ordered my KX3 kit today. Next I need to figure out an antenna for home that will work with my restrictions.