I am writing from a liveUSB made with Unetbootin and the menu was a little confusing. I also use Rufus, and it skipped the menu and went strait to the desktop. From what I've heard the people at Unetbootin are very helpful and they would help with problems. (They are also a small 2 man team, I think) They could also put SolydXK on the list of distros that could be downloaded from within the app.I cannot do anything about that, except for creating a custom application to put SolydXK on USB.
Here is one custom Unetbootin made for ZevenOS Neptune. http://www.zevenos.com/download/zevenos-neptune-2