That looks to me like you won't have room for your head. If you do, your breathing will most likely mist up the canopy. My hinge is slightly rebatedbut it doesn't really matter if it isn't. What matters is that the screws are countersunk flush.

Yes, it looks way flat to me.
Before you bolt anything I recommend you to sit under that canopy for a while and start doing some movements for while just to make sure you fill comfortable in such reduced space.
It seems very unsafe; will you be able to reach anything from the floor just in case?

also might think about if you can escape in the event of a forced landing on rough ground causing the a/c to flip over on the canopy. it happened to me.

monte