This is what was used in the Diablo Roadster but there are other ideas as well:
For the front of the roof/windshield pillars (there is also a set of clips and bracket as well in the front of the roof)
For the Roof and the engine bonnet:
NEARC's Blue Roadster
The pins are mounted on the roof and as you can see the latches are on the engine bonnet. You push the roof on the engine bonnet and it will latch on, same if you put it on as a roof, push to latch on, to release the roof you use the handle, the latches are spring loaded. Almost like OEM, make a cover box and cover the latch on the engine bonnet like OEM. You can even use 2-WIRE ACTUATOR to control the latches electronically...
I have them
CCIE