No projectile is going to have a linear drop. My disatisfaction with Crossbow optics is that they only give around three dots and, those dots aren't spaced far enough apart to cover significantly different points within common FS effective range.
When it comes to the Tiberius, Killjoy, or even the riser posted above, while they don't have infinite adjustment they do have enough adjustability so that one could simply pick the nearest adjustment point and, hold over or under. Granted it's not perfect but, a 90% solution. The general theme being , the more points of adjustment, the better.
The HHA optimizer allows for full adjustability between the zero range and out to 70yds because it uses a non-linear curve. The maker claims that it will work for nearly any projectile in our speed ranges and, Trinity swears by it. I can't vouche for it myself but, I suspect it will work (I had a lengthy convo with the braintrust of that product). The only limitation being the range (70yds). If that could be extended out a bit, It'd be a perfect solution (albeit expensive).
Whatever the case, the bigger problem facing most paintball players (and even myself) is accurately ranging the target. We are simply not built to do this without a lot of practice and accurate feedback. There are tools for doing this but, the better they are, the more costly they become.