Test anchors for on the fly mark attachment

I was wondering, is there a way to test anchor positioning for baseglyph-mark combinations that don’t exist pre-composed in the font? For instance if I wanted to put an ogonek anchor on B without having Bogonek in the font.

Thanks for your help.

Just have a ogonekcomb with an _ogonek anchor and an ogonek anchor in the B. Then use the ‘Show mark Preview’ plugin from the plugin manager.

Perfect, thanks!