Using a plaster reattachment adhesive to stablize your existing plaster is the best and shortest way to a repair. This will result in a flexible bond being redeveloped between the plaster and the lath resulting in a fundamental reinforcement of the wall system. Screws and metal washers provide a rigid narrow point of attachment often resulting in crushed plaster as your building moves. With only compression to secure the plaster to the lath they provide no structural reinforcement to the wall, only superficial stability. Also screws and washers necessitate substantial mud work to cover them changing the plaster surface. Screws and washers take about twice as long to repair with and is harder to do. Adhesives leave nothing on the surface to cover. Securing your plaster to stablize it is the single most important thing to in plaster repair. After that it is all cosmetic.