Here is my 2 1/2" 686+. It also has night sights as I prefer night sights on my concealed carry handguns:
It's already a 40 oz handgun (loaded), which isn't an issue if you're using a proper dual thickness carry belt and a good IWB holster.
But the 2 1/2" versus 3" barrel is a mixed bag. The 3" 686+ is going to be a little heavier still, but a 3" barrel is more ballistically efficient with .357 Magnum.
A 3" barrel also allows for the use of a full length ejector rod, which is useful ejecting the longer, and higher pressure .357 Magnum cases, which are more likely to stick than the cases from a .38 Special or .38 +P load. The full length ejector rod is why the FBI adopted the 3" Model 13 rather than a 2 1/2" barrel - it's a good compromise for concealed carry.
Since I shoot .38 +P self defense loads, I opted for the 2 1/2" barrel. However, if you want a 3" barrel but want lower weight (and are ok with 6 versus 7 rounds) a 3" Model 66 is an option that will shave off about 4 oz of weight.
The sizes are very similar and my 686+ and 66 fit the same holster. Model 66 on the left and 686+ on the right: