F/O,
I'm not sure if this will help, but nothing ventured nothing gained.
The DH8-300 has a Type I exit on the starboard side at row 1. It is a floor to ceiling exit, and when opened, opens outwards. It is not a plug exit.
There are two Type IV exits, one each side of the fuselage at row 10. These exits are plug exits, open inwards, and extend from about the height of the seat squab to the underside of the overhead lockers.
DH8 100 & 200 have Type IV exits at row 4 but don't have the Type I exit at all.
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bottums up !