Custom brim or raft?

i managed to fix some issues a bit now, but is there an option to print a smaller or custom raft for the part?
i noticed that it created a huge part of its own as a raft, but even that started to warp the edges, so is there an option to change the raft parameters somewhere to make it into some triangles around the part instead of this huge ship atm ?

Use a Brim of 8-10 lines.