Custom shaped nets are cheaper than I thought. They don't have to be one piece. You could have one ridged mounted below, to keep your legs in. And an upper, removeable, So that you can escape. But I would have one built to cover the ENTIRE door opening.
I don't much care for the bar right in front of your helmet. A funny car type cage is to protect you from Top impact,,,,,It should be in front of your helmet, but above it.
I like that you have a lot of bars, in the shape of triangles,,,,But I also like a clear escape route. In case of fire [your firebottle is not big enough, it never is) You can't get away from that thing fast enough.
And I don't like the seatbelt mount. That eye-bolt thing, My son's great dane has straightened out several of those.
Good luck, RICK