The spacing and arrangement look perfect! Nicely built.
The only comment I have is it looks like the grates and firebox are very long. If they are much longer than 20 inches you are going to have a hard time keeping wood over the whole area and if there is an empty area, draft air will bypass the fire and cool your flues. Even if you keep it filled it is really not the most efficient setup.
If you can figure a way to shorten up the firebox and raise the arch floor under the drip flues you will be way ahead.
John
2x8 Smokylake drop flue with AOF/ AUF
180 taps on sacks
75 on 3/16 tubing with shurflo
Eden Prairie, Minnesota