I hope everyone is sitting down, as I'm going to say something nice about 350's ....
I found them to be great longline aircraft, and no sweat at a mere 5'9" tall with the PacMan window or not. The trick is to go big, don't even attempt a 50' line, go 100', or better yet, 150'.
With the floor window, you may not see the load in flight, so fly the line, and as you reduce speed on short final, voila, a load appears in your field of view, just where it's supposed to be.