5'6" down here, so that might explain why we both lowered our column.

I also have a 300mm s/w and found out that if I use too long spacers it was quite difficult to get out. I made a small compromise and my mock-up is a little higher, but with my s/w the bottom is curved upwards (inwards to the center), which gives even more space than a D-shape s/w. And yes, I also rise the tilt when I get out and lower it back after I get in. Looks like we found pretty much the same solutions/habits, might be to consider for anyone around our heights.