I've already looked up phrases like "pilot commissioning", "test launch", "pilot launch", and many more. I can't think of anything that doesn't sound weird. Any comments? This is the sentence I'm trying to compose: "10 percent of the contract price after ... and provisional handover". What should I replace the ellipsis with?
You either commission work or you do not. You either set up a factory or do not. Factories are not usually set up "on an experimental basis".
I think you might be looking for: after the factory becomes operational on a trial basis. Trial basis is used. Not experimental. Hope that helps.