The most cost efficient and quick way to slightly raise a standard popup sprinkler is with a 15mm M&F adapter. You can also by a 15mm cut-off riser which can be cut to any height for the more OCD people. If the sprinkler is being replaced then first I would check the size of the popup itself. Usually if the system was installed by the home owner it will be a 2 inch hardware sprinkler which can simply be replaced with a 3 or 4 inch sprinkler. This will solve your height problem for ever giving you a larger popup itself and a larger rise while running.