I'm sorry for the late reply (please use my support e-mail for questions, I reply more often there). Regarding multi-digit dialing, this can be enabled in the main add-on in the Options page / Short-keys tab / "Enable access to more than 9 dials".
I know this add-on is not perfect, however due to many limitations in new Webextension API some features are just not possible. But there are more features coming later (especially the multi-digit dialing will need more upgrades...)
