I think you may be confused.. the "second half" of the sleeve (which is a misnomer, as the sleeve stomach is PART of the duodenal switch, but the switch is not the "second half" of the sleeve.. and it is usually done in one shot these days) is called a duodenal switch.. the RNY is not any part of the sleeve and consists of an entirely differently created stomach, removing the pylorus from the food path and creating a stoma. You need to research a lot more.. the RNY has very limited caloric malabsorption (you malabsorb nutrients for life) that fades to almost nil at 2years out, then you are relying solely on restriction. The RNY has a stoma, and the stoma is prone to stretching, which would leave you with far more capacity than the sleeve has.. Add to that the possibility of reactive hypoglycemia that may happen years down the road- there are numerous reasons why the RNY has a high regain rate..
Your rate of loss is not bad at all- 50 lbs in 6 mo plus what you lost before? I highly doubt a surgeon would revise you at this point in time. You are far from failing with this surgery.. slower loss than you'd like is not a valid cause for a revision. I think almost any surgeon would tell you this.. Plus 6mo is just the start of the process, you are very early out, way too early to be calling for another operation.. Please continue tracking every bite, staying on a valid post-op eating plan (there are many floating around if you don't have one from your surgeon) and keep working with what you've got, you've come far already.. no need to start sniffing out a faster fix, those "fixes" come with dangers like post-op complications, and if you do the RNY, there's just way too many to even list.. (google the published medical studies on short and long term complications of the RNY, it would likely change your mind.) The DS is the only one I'd consider if I wanted malabsorption, but it comes with a rigorous learning curve of vites, and labs, and being your own medical advocate.. Good luck!