I had done my rumble-seat in a hurry one night, but not my front seat as of yet. The rumble area has the rear frame bolts about centered on the seat - I used these even if a little too far forward on the seat as they are safer than nothing.
I had a friend with 4 grand-kids aged 9 to 13 years old coming over that night for a ride. Nothing like hearing the squeals of laughter from two 13 year old girls or 9 -12 year old boys coming from the back seat, and I know the four of them will become old car people when they are older. One of the girls has already made claim to their grandparents 13 T Runabout, and the other is pushing them to find an A Roadster - not sure about the boys - they might be more into something with speed...
I'd be interested in how you make out with the front seat.