Thanks guys. I was tinkering yesterday, and I think I came to an acceptable solution: use a short dogbone looped around the end lashing, tucked into the hammock with the "eyes" ends, stick the ridgeline through those eyes, and use whatever as a toggle. It only made my ridgeline about 4-5 cm longer.
That's a really difficult explanation to what is actually a relatively simple solution.. I should take a picture..
For the moment I stuck a carabiner in there, I might make me some aluminium toggles (which I anyway planned on doing for my whoopie slings). And if it turns out those few cms made the ridgeline too long, I can just do an alpine butterfly and I'll have another little something to hang things from..