sorry for the late answer but I was on holidays in Peru (wonderfull trip!!!!)
1) the program is online, not available for download but available to use (even if it is not a "full public" version, cause we are still working on it... some features ar not finished yet)... maybe you can write to Fabrizio Borgia (in CC), the software developper, to ask where you can see it by your eyes (I use a "personal" version on a specific website, but is my research working space, so if you add signs you will change my statistics)
2) SWift is very different from SignPuddle... it has the same use, so you can compose signs in SW, but the architecture of the software is brand new and also the organisation of the glyphes of SW (is organised on my classification... see my phd thesis). So it doesn't work with a system of "chineses box" ad SignPuddle, but with a "dicotomic" choosing system... you also have new features as the "ad hoc" glyphes composition (see my thesis)... is hard to explain by mail... you will see when Fabrizio will tell you the website.
3) you can do both, single signs and text
hope the answer will satisfy you