I've used several. It honestly depends on the colors in the spectra. Just make sure you remove as much sanding dust as possible. I've found that using the sticky side of duct tape works great!
If there are light colors - especially the natural/white layer - I stick with CA or Solarez. The colors seem to bleed over less with those 2 (but still can!).
I've also used Pens Plus but the yellow-ish tint will cause the colors to look different. They tend to darken. If it is mainly dark colors I'll use Pens Plus OR the CA/Solarez.