Dear Mr. Walia,
I read your all threads on askyogaexpert.org.
You may continue with Naadi-shudhi pranayama which involves alternate nostril breathings without retention. Inhale slowly and deeply while being aware of every breath - how it touches the internal walls of nostrils and goes inside the lungs - just feel every breath. No need to retain after inhalation or exhalation. It can be followed by Brahmari pranayama too.
To solve your b.p. problem, you need to work on reducing your weight as well as diet restrictions on salt, sugar, non-vegetarian and alcohol or discuss with your physician to change your lifestyle and diet.
You can also practice sectional breathing which has good results. If you are interested, kindly write back to me and I will elaborate here.
Also if you can mention your working hours, and family history of b.p., or other chronic ailments, we can slightly discuss with you.