Nawaafil

Four rakaats after Zuhr and Isha

Q: Great virtues are mentioned in the Ahadith for praying 4 rakaats after Zuhr and Isha.

Should one perform these apart from the confirmed 2 rakaats sunnah that are prayed after Zuhr and Isha i.e. first 2 rakaats and then 4 rakaats? And these 4 rakaats should they be prayed with one taslim or 2 by 2 rakaats?

Four Rakaats after the Fardh of Esha

Q: Praying four rakaats after the fard of salaat Esha is mentioned in Ahaadith. Its mentioned that the virtue is that one will gain reward as having prayed these four rakaats on Laylat al Qadr. There are both Marfu and Mawquf reports regarding this. Should this be prayed after the 2 rakat sunnah muakkadah as adding 2 rakaats seperately or adding 4 rakaats either seperately or in two sets? 

I read in Qutul al Quluub that Ibn Masud (RA) did not like to pray after the Fard a same amount of Nafila rakaats, they would pray Isha and thereafter 2 rakaats and thereafter 4 rakaats. Is this true?

In Musannaf Ibn Abi Shayba 2/206 there is a report from Umar (RA) that he did not like to pray after Jumuah the same amount of nafil i.e. 2 rakaat. What Ibn Masud (RA) would do, is that 2 rakaats and thereafter 4 rakaats with one taslim?