Ruling on not doing some mustahabb deeds in order to open the hearts of the people of bidah whom one is calling to Islam
Praise be to Allaah.
Firstly, if you are doing an action which is proven to be part of the Sunnah of the Prophet (peace and blessings of Allaah be upon him), it is not right to say that you want to make some changes to it, because it is right and proper in and of itself. But the reason behind your question seems to be that you want to keep from doing it openly in front of some people for a specific purpose, or to avoid a specific evil.
Secondly, talking about Tawheed and basic matters of aqeedah and teaching people about these things among the people you describe, is undoubtedly more important. Tawheed is the key to the call of the Messengers (peace be upon them) and the first duty of the one who is accountable. It is the condition for all other deeds to be accepted. If it is clear to you, or you believe it to be most likely that adhering to some mustahabb actions, such as moving your finger etc., may cause confusion or fitnah, or cause you trouble, or damage your reputation so that people are put off you and do not listen to you, or distract the people you are addressing from what is more important, then there is nothing wrong with not doing it for this reason in these circumstances. Allaah knows best what your intention is, and that you are not giving it up out of negligence, but in the interests of spreading Islam, so you will be rewarded for this, in sha Allah. May Allaah bless our Prophet Muhammad.
Sheikh Muhammed Salih Al-Munajjid