It depends on both a size of the stomach stump left and length of the intestinal loop. In case you perform Hoffmeister-Finsterer modification, the jejuno-jejunostomy is needless.
An initial temporary stenosis of gastrointestinal anastomosis not only in afferent loop (AFS)
but also in the efferent loop (Vomitus and delay gastric emptying,endoscopic image of oedema of efferent loop) lay to keep the nasogatric tube sometimes 15-20 days when the oedema usually subsides.So I strongly believe that jejunojejunostomy is valuable in BII anastomosis.
The most comprehensive books describing surgical techniques in gastric surgery I ever read are “Studies of gastric surgery” by S. Yudin and “Digestive tract surgery” by A.Shalimov & V.Saenko. More than 70 technical modifications of BI and BII reconstruction after gastrectomy are described by authors in these books. This issue was important some 20+ years ago when ulcer surgery was relatively frequent operation. Nowadays those classical readings are somewhat forgotten, however I can highly recommend them for anyone who is interested in reconstruction methods after gastric surgery.
I may add "Gastrectomy" by Rusanov with marvelous illustrations. Unfortunately, the three books are in Russian, and, to the best of my knowledge, have never been translated into English.