Yes, the speed brake can be skipped but for the minimal amount of work it is to install..... I suggest you do. The flaps create enough drag to slow the airplane down but can also make the tango difficult to land. I have been using speed brake only to land the tango, the flaps tend to give too much lift making it difficult to actually plant the plane (especially with the NG strut too long). If your using a smaller engine (12lbs) you may find you dont even need the SB to land but, I believe on dead calm days you'll wish you had it.
Todd