The big yellow gun is my first 170. I completed it months ago as a test of the parts fit and instructions. Not a bad kit, but certainly not an easy model. I was not enthusiastic to build five more, the only difference between the 170 and the 210 is the length and girth of the barrel.
Working on another 170mm. The barrels are turned aluminum and are perfect. I built all five at the same time in an assembly line style. It's about 300 parts for five of them.
The prototype and the five others, 2 of the 210 and 4 of the 170. The 210 was used in batteries of 2 or 4, I figure late war they get two. The 170 was used in batteries of 4 or 6 and I figure the 4 gun battery for late war use. My Panzer III artillery towing tanks will tow the four 170s and I intend to use a couple Paul Heiser Models Panthers to tow the two 210's.