It’s too bad they couldn’t come up with different levers. But if you tune in C, wouldn’t that cause more stress on the E’s & B’s to begin with? Grant it this solution eliminates the need to flip the levers, but if you want to play in the key of F you’ll be stuck. Hate to see you sacrifice key versatility- I would wait to see what the technician says if it were me.
But ultimately I think the point is that what is more important is allowing the harp to acclimate to the environment and keeping it maintained and tuned rather than “warming up” in terms of giving a little playing to get it ready for some ‘REAL’ playing.
So long as the harp is physically warm enough, and is in good working condition, there isn’t any reason to need to give it a warm up that I can think of.
I think any perception that the harp plays better after a warm up is really just the player warming up, not the harp.