2 inch vs 1.5 trap for kitchen sink

i have a 2 inch pvc 90 stubbed out under the sink....i was planning to install a 2 inch trap then use a 2 in to 1,5 reducer to connect to the tail piece

or would it be better to put an a 2 inch adapter at the 90 and use a 2 to 1.5 inch lock nut and step it down and use 1.5 for everything

which would be the better job?

 

drain

Neither way is necessarily "better" and both are equally adequate. Because of the long term benefits, I would use the reducer on the 2" and 1 1/2" tubing for the rest of the drain installation.

 

thanks HJ i just though maybe the 2 inch would having things flowing better...the 2 gal i replaced was down to about 3/4 with all the build up