[gydrorway]

Jazak Allah Khair brother (ustadh) silat. May Allah raise your rank and increase you in knowledge.

Regarding witr, let's say you are praying witr as 2+1. Do you sit in tawarruk position at the end of the 2? Also, should you do opening supplications (inni wajjahtu...) in the last rak'ah before the fatihah?

According to Imam asy-Syafi'e rah., sitting in tasyahud akhir / last tasyahud (ie sitting in tasyahud where after it there is salam), should sit in tawarruk position, whether it is for solat of 1 rakaat, or 2, or 3 or 4 rakaats. This view is also supported by Imam Ibnu Hazm rah.

Although there are ahadith regarding sitting in iftirash position when arRasul s.a.w. prayed 2 rakaats, ulama of Shafi'e school have explained that the ahadith as daleel are of mutlaq nature (ie has general meaning) compared to other ahadith that specifically mentioning sitting in "tawarruk position" in the final rakaat of salat.

wallaahu a'lam.