a silly minor oversight on a fantastic bike.
Kev is right - a little practice does make it easier.
The trick is to put the screws in without the seat in place so that you make make a mental note of the angle they go in at.Then remove them,fit the seat, and screw them in again - at the correct angle.
I owned bikes in the 1970s that had good simple hinged seat access and keylocks - its like they've tried to reinvent the wheel :???: My 1970s bikes also had helmet locks.
Grant