i run an FBM slim rail, but slim pivotals are nice, fit ECCD for lightweight.
also get some lighter wheels. if i remember correctly, those wheels aren't too light. go to sicklines.com, and at the top corner click weights. check in there, i think its all mtb stuff. a light rim is the dt swiss ex5.1d, claimed 500G i think, buit its maleable metal, so you wont be really getting pinch flats, and if you want to make it look nice, you can take a rubber mallet to the rim to get rid of flat spots.
hmmm, maybe a fit eccd? not sure how it is maybe someone will know but all i can say is do not get the transition seat unless you hardly sit down, it looks comfy but it actually pretty hard