It's not the answer you want to hear, but I bought my 2x P6248 with the accessories. So I'm using the legit tips.
The most useful tip is the "TwinTip" offset needle 016-1786-00. Followed by the "Longhorn" twin tip 016-1780-00. At least for my purposes. And for probing where lead length is not a major issue, the 196-3434-00 "Y-Lead" adapter is useful. The tip saver is a good idea if you use the probe often, but is optional if you're gentle with your probing.
If it helps, the diameter of the needle tips is exactly 0.025". You might be able to find some gold plated needles and bend them into the shape you want. You'll probably also want to provide some additional support like the original. Although it might be tempting, don't try to make needle probes out of 0.025 *square* posts. It will ruin the contacts in the probe if the square post tries to rotate in the probe socket. (Guess how I know...)
You can make a "Y-Lead" adapter with a piece of 2x1 regular 0.1" header. Square pins is ok here since they won't rotate.