The TSGG is built with circuit boards and so is somewhat easier to assemble, IMHO. It also uses the more common tube, the 12AU7, which ofers more opportunities for tube rolling. For a newbie, working slowly and deliberately, I would think four to six hours for either kit would be about right. But that is just a guess.
There are several excellent online tutorials for how to solder. Lots of us do it. It does involve a degree of manual dexterity, but most problems that you might create are pretty fixable, and you will have the pride in ownership of having made something.
Both manufacturers have excellent forums to help if you get off of the track and you can always register and ask the questions directly of the manufacturers and end users there.