Take two aluminium ladders, dismantle one and use the components to double the number of steps in the other. Now there is a perfect height to stand at for any objects that my scope can see.
The seat:
There are times when an old bloke like me gets tired of standing. Now with my moveable seat I finally get to rest a little. This seat also means the ladder, which is mainly needed for the big Dobsonian Newt, can also double as a chair behind the refractor.
The seat is made from hardwood marine ply and can be installed on any of the steps which are 140mm apart.
To further cushion the blow, some closed cell foam will be added to the seat after Easter ....
One does have to ask though .....where did the measurements come from for the seat
Lot of "science" went into the design and measurements.....
I was paddling my Epic V7 Ocean Ski the other day and when I got home still with my wet shorts on, I sat on a bench leaving a wet mark.... then it was just a case of getting the vernier calipers out and hey presto !!! We have a seat
I like your style Matt: looks great. When I saw the piccies I immediately thought "What about a cushion?", but you covered that straight away! It would be a pity if you couldn't see that lovely wood finish though.
Re Morton's comment: it would be easy enough to drill a hole in the shelf for a cup holder...
(Or eyepieces for that matter!)
Keep up the good work: and I look forward to seeing the eventual seat that you make.
Ivan 
I fall over enough these days without any encouragement Morton....
