Yes, you would have to synchronize your LV2 with your FP control/indicator. Likely the biggest slowdown you're facing is that operating on controls/indicators can only work in the UI thread, while most code can work (often in parallel) in various other threads.
I vaguely recall someone posting about doing something like that before; at least related to not wrapping. An XControl would provide the encapsulation you need, I think, but XControls are not necessarily for the faint of heart.
Are the value non-sequential AND non-contiguous, or just non-sequential? If it's the former, play with values in the unassigned spaces between values and see how it handles coercion.
neil does beg a good question, however - seems like an awful lot to dig through for a user. Maybe it could be broken down into three or four separate rings and selected in stages (e.g., the Add A Vehicle pane on advanceautoparts.com)