Is there a better way to connect these parts?

I am making a chair and experimenting with various seat forms to see which is most comfortable. I have printed in six parts because the seat is 550mm wide. To save on time and filament, I am printing a 10mm shell of the form that eventually be made from foam. I am using 5mm diameter printed dowels to help with alignment and then supergluing them together.

This solution is somewhat time consuming and there is a risk that the superglue comes apart in a sit test if parts are not perfectly contacting each other.

I am wondering if there is a way to connect them together with some good clamping force. I’m thinking of barrel nuts and screws but I’m not sure if it would work to be able to tighten the screws without making large cutaways in the parts … or very long holes tangent to the part surface that are too deep for my Allen keys to reach.