OEM is tpyically DENSO for Honda and you can buy the same DENSO part numbers direct from Oriellys or Advance for a fraction of the cost.
The only DIY cleaning of injectors I have technically done is soaking the injectors in a jug of seafoam. A pressurized system would definably be a better solution. However the detergents in Exxon/Shell 93 octane do a REALLY good job of cleaning injectors. Id just fill up on a tank of 93 and see how it runs on a tank of 87 after that.