Pressure Regulators with drip system

[greenwall]

Hey! I have a question regarding pressure regulators for a drip irrigation system.

Background:

Recently I had a sprinkler system put in my back yard. In addition to lawn sprinklers, I have several lines going to various planters (all full pressure, i.e. ~100psi). One of these planter lines has three standard 1/2" stems that emerge at three evenly spaced locations along my patio whose purpose is to irrigate potted and/or hanging plants around or above my patio.

Problem:

While I feel like I did the right thing in anticipating having water access available near my patio for future planting ideas, I did not realize that 1/2" pressure regulators were uncommon (if not non-existent). Since these three patio outlets are attached to a line which, further down, requires the full pressure, I can't put just one regulator on the line. Instead I have to put a regulator on each of the outlets if I decide to use it for watering potted plants via drip tubing. But I can't find any 1/2" regulators!

Question:

Do 1/2" pvc pressure regulators (to 25psi) exist and where can I get one (er...three)? And if not, would it be OK to attach a 1/2" to 3/4" adapter to allow me to use a 3/4" riser (and thus readily available 3/4" regulators)?

If I went the adapter route mentioned above, I was worried that going from 3/4" (main line) to 1/2" (approximately 1 ft) and then back to 3/4" (for the riser) I would negatively affect the water pressure somehow.

Any help would be appreciated! Thanks!!