Parameterized Skadis Universal ring holder

I started off with ripetomatofetish's great round holder for the universal Ikea Skadis hooks. However I was missing a little bit of offset between the ring and the baseplate. In the end I did a major overhaul and added a number of parameters to easily adapt it to different needs.

Requires one Skadis_Universal_Hook from CSD Salzburg's IKEA SKADIS Universal Hook Set.
No support needed.

New features include:

• Parametric distance between ring and base
• Parametric height to decouple ring thickness from ring height
• Parametric cutout at the front of the ring (Handy for things that won't fit through the ring from the top, like my chisels)
• curved part of the connector scales together with the ring height to give a better visual impression
• in case the ring height gets too big, the curvature of the connector is minimized to prevent obstruction of the mounting hole
• added assertions to check parameters for plausibility, i.e. you're not allowed to block the mounting hole by a ring being too high
• moved all user-modifiable parameters to the top for improved convenience

New features include:

• Parametric distance between ring and base
• Parametric height to decouple ring thickness from ring height
• Parametric cutout at the front of the ring (Handy for things that won't fit through the ring from the top, like my chisels)
• curved part of the connector scales together with the ring height to give a better visual impression
• in case the ring height gets too big, the curvature of the connector is minimized to prevent obstruction of the mounting hole
• added assertions to check parameters for plausibility, i.e. you're not allowed to block the mounting hole by a ring being too high
• moved all user-modifiable parameters to the top for improved convenience