The servo rudder you are looking for is here, all sizes and mounting types are available!
Reference 04SRT-TRX7
Brand: SRT
2 holes 24mm 25T SRT steering servo horn with offset - SRT-TRX7
Reference 08293422
Brand: HUDY
ALU CLAMP STEERING SERVO HORN - EXTENDED 8mm - 25T - 293422
Reference 08293409
Brand: HUDY
ALU CLAMP SERVO HORN - FUTABA, SAVÖX - 3-HOLE M3 - 25T - 293409
Reference 04SRT-TRX6S
Brand: SRT
1 hole 25T SRT steering servo horn with offset - SRT-TRX6S
Reference 08293493
Brand: HUDY
ALU SERVO HORN - FUTABA, SAVÖX - OFFSET 1-HOLE M3 - 25T - V2 - 293493
Reference 04SRT-TRX5S
Brand: SRT
1 hole 25T SRT steering servo horn - SRT-TRX5S
Reference 08293351
Brand: HUDY
HUDY ALU ADJUSTABLE SERVO SAVER 1/12 - SET - 293351
Reference 08293403
Brand: HUDY
ALU CLAMP SERVO HORN - FUTABA, SAVÖX - OFFSET 1-HOLE M3 - 25T - 29340
Reference 08293499
Brand: HUDY
ALU SERVO HORN - FUTABA, SAVÖX - 2-HOLE M3 - 25T - 293499
Reference 08293502
Brand: HUDY
ALU SERVO HORN - HITEC - 3-HOLE M3 - 24T - 293502
Reference 04SRT-TRX6
Brand: SRT
2 holes 25T SRT steering servo horn with offset - SRT-TRX6
Reference 02UR1804
Brand: ULTIMATE
ALUMINIUM DOUBLE ARM SERVO HORN (23T - SANWA/KO/JR/AIRTRONICS) (1pc.)