hi there! well my twist outs usually last me about a week. One of the methods that I’ve tried and also like is two strand flat twisting the roots and then just twisting the remainder regularly. Maybe you can try that too. I usually retwist every other night in bigger twists to go to bed and wear a satin bonnet. The overnight maintenance is really key for me. Right now I use a mixture of shea moisture’s curl enhacing smoothie with ecostyler gel. The ecostyler has nice, touchable hold for my twists. Bantu knots are the shizz on wet hair for me. When I try it on dry, it’s…a lil bleh. puffy, just eh and it only lasts me for like 2 days. I use the same products for that style right now. I have become pretty partial to the ecostyler gel mixed with…everything. 
This is an old photo of a fresh twist out of mine. The next few days, it’ll just grow and get more voluminous.