The Senior 20 is slightly larger than the Busker, and has bigger bellows, a fast rewind system for the paper rolls, and a multifunction 'conductor' standing in front of the pipes. It is intended to be used on a cart, or on a table top.
Any reasonably practical person can build the Senior 20, and the package supplied includes instructions, drawings, and a video. A minimum of machinery is needed - although a small bandsaw and pillar drill would be advantageous - and the methods used are fairly basic. Some previous experience at making things (ideally working models) basic woodwork skills, and the patience to cut out all the little bits that have to be stuck together, does help. You need to be prepared to read and follow the instructions, and to watch the DVD to get the final details. You also need to be able to work from basic drawings - if you need full engineers drawings with every small detail shown, then this package is not for you! There are lots of A4 pages of instructions and drawings. Along with the DVD or Video, there is a paper test roll.
The only aspect of the construction that might cause a problem to someone without metal workshop facilities is the fabrication of the crank used to operate the bellows. If needed, help with this can often be supplied by the local model engineers club, or the metalwork department of a local school or college. Alternatively, there are companies who offer various parts used in the construction of the Senior 20, as ready-made items - such as Roll Cutter - and these are listed on the Links page.