My dilemna is that I am having a new countertops installed (Silestone) over exisiting cabinets. The installer said that the cabinets need to be level to within and 1/8". They are currently off by 1/4". They are two L-shaped counters and the backs are higher that the front. I recently had laminate flooring installed so it is difficult to get under the front end of the cabinets to install shims. Any suggestions?