the lower limit might be the cats of the charles du gaulle. that is, you can make short but powerful steam catapults, but the ones on the CDG are IIRC considered to be a bit too short due to the high acceleration.
CDG cats are 75m, the Rafale M is 22,200Kg's fully laded, Hornet C/D 23,500Kg's. if similar principles to the RN are adapted ie extendable nose wheel to increase attack angle on take off, the Hornet is sound. Hermes in her pre Commado carrier configuration could shoot off a 22,000Kg fully laden sea Vixen and 28,000Kg fully laden Bucanneer S.2.