Inside College Volleyball is more geared for women, which reflects the unfortunate imbalance between college volleyball for men and women. I find it interesting that volleyball could be the only collegiate sport in which the men are supported significantly worse than the women.
I am glad that Inside College Volleyball is of value and that you are applying/reflecting the recruiting plan in your process. The men's club season is broken into pieces, which can disrupt the protocol a bit.
As to your specific questions:
1. I would send introductory letters to college coaches in the late fall/early winter. Men's volleyball tends to recruit a bit slower than women's volleyball; which may be due to the young ladies physically maturing quicker than the guys, or that the men's college volleyball coaches still have a sense of balance.
2. Wait to take video as late as possible in the late fall/early winter. Men's volleyball is so physical (when compared to women's) and the college coaches want to see/evaluate the level of physicality. Again, as young men mature a bit later (there was a huge difference in my physical stature between end of freshman year and start of junior year), you want to wait as long as possible on the video to adequately reflect this physicality.
3. I would send a second letter just before the start of the National Championships; like a reminder letter. With this second letter, include the most recent video possible; from practice just before the tournament.
Glad to help and I should be able to provide a bit more background on men's volleyball in these coming months, as I am producing a boys' volleyball recruiting combine down in Puerto Rico in August. As we will be promoting this event heavily to men's collegiate coaches and the local players, this should assist in my continuing education!
In closing, I would also strongly suggest NCSA Athletic Recruiting as an invaluable resource/support for male VolleyFamilies - Men's College Volleyball provides such limited opportunities (when compared to women's) that the competition is fierce for scholarships and roster spots; any advantage or leg up is well worth it!