i really appreciate all the feedback and responses. I was going to get the 40# so i could use one wing for either singles or doubles. Is there such a thing as the wing being too big for singles?
Yes, there is such a thing. A wing too wide/large will fold around the cylinder- like Mexican Tacos- it will not only look weird, it can also make difficult emptying during ascent.
Some posts mention "servicabilty" and parts: a Back Plate doesn't need service! The harness, after maybe several years of diving may need replacement, and being a 2" webbing it doesn't really matter where or which "brand" to get. Mine and wife's are like 20 years of intensive diving and the harnesses are showing age but still the original ones.
Wings do suffer from aging, the Halcyon ones both suffered from the fabric fraying at the seams after couple of years, they were replaced several years ago. My son's Mares XR wing also frayed in similar manner after single year. I have other wings Hog and one I DIY. Halcyon wings also at some stage the threading for the corrugated hose completely detahced, cannot be repaired needs replacement of inner bladder.
Good news is that it really doesn't matter which wings are paired with the BP- most have the same disatance between holes, and most BP have several holes, some are oval shaped.
Bear in mind the cam band slots, some BP and wings do not have them (my Halcyon eclipse don't) and must use STA.
When I'd need a new rig, I'd probably go with dgx.