Wouter,
Chined boats usually change the angle of the chine along the hull and if this is the case and you are not building to be measured by templayes you could wire the panells together and fillet and glass the joins.
Now if you design a boat around chines of constant angle along the length of the hull you could glue and screw to lengths of cedar along the chines and this while a bit heavier would probably be quicker. This will restrict the shape a little and getting it to look good may be a bit of a challenge as may appropriate bouyncy distribution. You would have to be mindfull of these when doing the design. Also not sure about how the narrower deck will affect tortional stiffness of the hulls. Remember there are no stays helping lift the hull. Most of this is coming off the front beam. This may not be a huge problem but would need to be considered.

You wouldn't build a hull in a day as a one off.

As the ply is only 8ft long and the boat is 12 ft you need to decide to scarf the ply or lap join it. Usually scarf.
That would be done in one day. So in order to get average building time down to one per day you would need to be building a number of boats in production line style.
Then it is still only assebling the basic shell.

Anyhow ths is all just guess work until the design is completed and building steps can be worked out.
The devil is always in the detail.