I had a 96x33x24 tank. Which I thought was kind of short and stubby looking. I had the opportunity to have the tank remade and I opted for 96x33x28. I can reach the bottom of the 28, its a stretch but I can reach it.
My tank is an open top, so it has a stainless steel frame and full access. Since there is only a 3" splash strip around the top edge reaching down the front to scrub coraline is doable - not enjoyable - but doable. I had a 300g 30"Tall fish only tank with standard acrylic openings, and reaching the bottom of that tank was darn near impossible without lying on top of the tank and putting my shoulder into the tank.