The servo rudder you are looking for is here, all sizes and mounting types are available!
Reference 04SRT-TRX6
Brand: SRT
2 holes 25T SRT steering servo horn with offset - SRT-TRX6
Reference 04SRT-TRX5
Brand: SRT
2 holes 25T SRT steering servo horn - SRT-TRX5
Reference 08293406
Brand: HUDY
ALU CLAMP SERVO HORN - FUTABA, SAVÖX - 2-HOLE M3 - 25T - 293406
Reference 08293422
Brand: HUDY
ALU CLAMP STEERING SERVO HORN - EXTENDED 8mm - 25T - 293422
Reference 08293499
Brand: HUDY
ALU SERVO HORN - FUTABA, SAVÖX - 2-HOLE M3 - 25T - 293499
Reference 08293493
Brand: HUDY
ALU SERVO HORN - FUTABA, SAVÖX - OFFSET 1-HOLE M3 - 25T - V2 - 293493
Reference 08293506
Brand: HUDY
ALU THROTTLE SERVO HORN - FUTABA, SAVÖX - 2-HOLE - 25T - V2 - 293506
Reference 04SRT-TRX7
Brand: SRT
2 holes 24mm 25T SRT steering servo horn with offset - SRT-TRX7
Reference 08293403
Brand: HUDY
ALU CLAMP SERVO HORN - FUTABA, SAVÖX - OFFSET 1-HOLE M3 - 25T - 29340
Reference 08293491
Brand: HUDY
ALU SERVO HORN - KO PROPO, SANWA - OFFSET 1-HOLE M3 - 23T - 293491
Reference 08293496
Brand: HUDY
ALU THROTTLE SERVO HORN - FUTABA, SAVÖX - OFFSET 2-HOLE M3 - 25T - V2
Reference 08293503
Brand: HUDY
ALU SERVO HORN - FUTABA, SAVÖX - 3-HOLE M3 - 25T - V2 - 293503