In September 2020, I came across pictures of this nice little Japanese guide to the series from twitter user; ruchishogun...
The X-Bomber Super Manual (B6 size / 72 pages) was published in August 1985 and a 2nd edition was released the following month.
The publication was apparently prompted by the rebroadcast of the series on TV Saitama that year.
I think that I might have found an image of the cover for the 2nd edition on mandarake.co.jp, where it was listed as "SVN (SUPER VISUAL NETWORK) X Bomber Launch Preparation Issue 2.1".
On the other hand, it may be something completely unrelated.