Well, I tried this. Its expensive but in my opinion worth it since I have cargo ships with 10 cargo holds, making them quite large and approaching the size of the construction ships.
I have seen however that it doesn't seem like civilian ships take advantage of civilian jump tenders at all, which is a shame. My own civilian ships can jump through fine to found colonies, but the civilian ones seem to wait till after the gate construction is completed. Least as far as I could see.
This is a shame, because for a next game I was considering Jump Gate-less play. That is, simply place a civilian ship equiped with 70k civilian drives and 10k military jump drives on every jump point I want to access, least on the more outlying colonies. They have inbuilt weak passives which I hope to use to detect incoming vessels and I can also withdraw them should I need to. This is an expensive strategy but doable since both jump drives can be pre-built. On that note, would civilian jump tenders be able to detect hostiles who jump in at 50k?