Dr Jonathan Kemp of Kemp Strings has designed custom strings released by Maurizio Über Basses (MüB) for 18 inch basses. The gauges in inches are 0.186, 0.138, 0.103, 0.077, 0.058, 0.042 and feature lumps for controlling inharmonicity and tapering customised to fit the large diameter bass strings onto the instruments. Achieving this on an instrument only just over half the length of a normal bass guitar is the result of an awesome collaboration with Maurizio in Malaysia.
You can purchase the strings through https://www.mauriziouberbasses.com/merchandise
Thanks!