I love the pictures in his book but his write up confuses me. He uses the title Stabsordonnanzen Garde-Korps. It is not clear to me who exactly he is talking about. On page 455 he clearly explains that there are no officers in the staff orderlies and then when you turn the page suddenly were talking about officers. I think there is a better writeup in the book by Herr and Nguyen where on page 590–591 of the English language version they talk about these dispatch riders. However, there is a real lack of photographic evidence. I think the best that I have seen so far is Brackmann. I do love the pictures in Stubbs and Randy's helmet definitely does not have a one-piece lobster tail. However, his has a spike similar to the one in Belgium. His spike base is similar to the one in Stubbs. Both of those 2 helmets have yellow fittings. Randy's does not.
So based on what you have seen what is Randy's helmet? I still do not understand what you are talking about reference the visors. I wish there were more photographs but it is possible that those of 1885 to 1887 are always misapplied if indeed they were wearing the uniform of their home Regiment. It is a really obscure niche here.
There is a picture in the old Almark book on pg. 86. This was not only discovered by Glenn Jewison but he also determined easily that he was misidentified. There is also this quote on page 87. "There is evidence that officers at least were allowed to purchase an extra polished steel helmet, probably of lighter weight, for off-duty wear".