You are quite right, 161-256 are silly. I honestly just did not think of this. What is especially embarrassing, is this did not occur to me once, in two years. By way of excuse, I was not really thinking much about the puzzle at all.
I will make up for two years of stupidity. I will spend from 161-256 to the unsolved parts, as you suggest. In addition, I intend to add further funds. My aim is to boost the density by a factor of 10, from 0.001*length(key) to 0.01*length(key). Probably in the next few weeks. At any rate, when I next have an extended period of quiet and calm, to construct the new transaction carefully.
A few words about the puzzle. There is no pattern. It is just consecutive keys from a deterministic wallet (masked with leading 000...0001 to set difficulty). It is simply a crude measuring instrument, of the cracking strength of the community.
Finally, I wish to express appreciation of the efforts of all developers of new cracking tools and technology. The "large bitcoin collider" is especially innovative and interesting!
I need some fund to continue for my discoveries and projects, or else I'll have to abandon these endeavors entirely. It's quite distressing for me, but I've been left with no choice. The creator's support would mean the world to me as I strive to keep my work alive. As you mentioned, "it is simply a crude measuring instrument, of the cracking strength of the community." However, if all members of the community continue to leave their tasks incomplete due to constraints, your measuring instrument will repeatedly break. Please understand that in this community, 99% of members may have limited strength, but they put in a tremendous amount of effort. Anyways... Today is my birthday
Keep on grinding!