It's a T50 if memory serves

 

I would love to see a picture when you get it done.

 

I can't caution more strongly against making your own seats! There's a reason they do all those crash tests. You can't just think your way through it
In a crash a human's weight (not mass) can go up to somewhere around that of a cement mixer. You can't figure that out in your garage.
Don't do it, you could get someone killed.

 

x1 I recollect my sister and brother-in-law not fixing their selt belts in the rear seats of my previous D2 some 14 years ago. On leaving a county farming show some idiot missed his turning and slammed on the brakes and then reversed down the road towards me. I was doing about 45mph and had to slam on my brakes and do an emergency stop. My brother-in-law flew forwards with enormous force and hit the back of my seat badly cutting his eye and forehead. I would reckon the braking deceleration increased his moving body mass by a factor x3 to 4. Not only did he risk his life but he could have broken my bl@@dy neck also. He only weighed about 145lbs. More people are maimed or killed in accidents by rapid deceleration AND items flying around inside the vehicle cabin and hitting them. Food for thought. I will never let anyone ride in my vehicles now unless they fix their seatbelts, it's also the law in europe today as it was back then.

 

Another matter to consider, by removing the seats the resonances and droning noises will increase considerably, bit like an empty van, and whilst that is tolerable around town or short journeys it could be intolerable on say a 300 mile trek on highways at 70mph. just a thought (the dog will maybe go mental )