The title says it all.
While anchors speed up construction process, you can't use preview without generating glyphs.
It is not one or the other. Anchors are tool to create composites quickly and consistently. When you have many diacritics positioned above/below certain character then use anchors. They are not very useful for positioning when only one accent is being placed and/or when the result needs to be decomposed and merged (e.g. aogonek, eogonek).
Nevertheless, if you find achors too confusing, just use composites. It is not such a big deal.
Note that anchors are not MM-compatible, that is their positions do not interpolate. You can fix that with some macros though. … or you can generate composites before interpolation.
Also, consider looking FLS manual for alias.dat. That can speed your process up a bit more.
Captured from web.archive.org on 29 Dec 2011. view this capture