If i were you I would make a timber buck like you suggested and use 200gsm cloth, 2-3 layers of 450-600gsm woven roving, and another layer of 200gsm cloth.
You can see photos of how I shaped a timber buck in this thread Demonseed 44 Enclosure
If i were you I would make a timber buck like you suggested and use 200gsm cloth, 2-3 layers of 450-600gsm woven roving, and another layer of 200gsm cloth.
You can see photos of how I shaped a timber buck in this thread Demonseed 44 Enclosure