I did my own research when I made my Prometheus line drawing. Wiki figures are way off from what is shown on screen. For example: the U-shaped superstructure around the tower has windows that can be easily scaled, 302s have to be able to comfortably fit within the hangers. In Ethong where the Prometheus was destroyed, the only time we saw a 302 take out of a hanger (those pods were originally supposed to be engines as older CGI models show the front glowing) the 302 had a ton of room and looks like two 302s can fit side by side. Prometheus can be anywhere between 330 to 450 meters long.
The Daedalus class is supposedly as large as 600 meters.
The Ha'tak is slightly harder. People based the size off of the Great Pyramid but in reality, those ships cannot land on pyramids because their base is triangular not sqaure.
Not to mention that there are really not alot of good line drawings or even good pics to make a size comparison from.
"Don't underestimate the power of technobabble: the Federation can win anything with the sheer force of bullshit"