I would just put both biggest used commercial and biggest used military jump engines on a jump tender and have a half a dozen of them on important JPs outside my JG net. Currently this means they have 15k military JE, 45 commercial JE and 9 strong commercial engines so that they are still commercial designs from maintenance point. They have bit of armor, multiple CIWSs, basic passive radar suite, some fuel storage capacity and 100+ months of deployment. For faster changes of tended JP they later get help from tugs.
So far I haven't manage to get so far in game to build anything that my Gatekeepers can't jump-tend.