In particular primary electronics of sensor systems is strongly subject to deviations and degradations caused by environmental and manufacturing conditions. Current approaches cope with these challenges by calibration or trimming techniques. More recent approaches from the field of evolutionary electronics offer considerable extensions, incorporating also issues of fault-tolerance and self-repair. State-of-the-art evolvable analog hardware bases on field-programmable-transistor-arrays (FPTA) and start from primal soup for each new problem. Our work deals with the crucial issue to efficiently include the wealth of existing engineering design knowledge into the otherwise attractive concept. For the practically relevant task of sensor amplifiers, a particular flexible FPTA architecture is developed, verified and physically implemented in a 0.35 ?m CMOS technology.