Steve deliberately made jump engines large, expensive, inefficient, and squadron-capable because he didn't want hordes of single ships flying around, jumping willy-nilly, and generally being blub*-like intead of being deployed in batle groups. Given that he added smaller-than-15-HS jump engines after repeated requests, you might get the single-ship version you're looking for but why not just use SM mode to double your race's jump engine efficiency and pretend that their max squadron size is one?
*blub here refers to some other 4X game where every ship is jump-, hyper-, or FTL-capable