Harvesting commercial yeast, may have made my starter too strong

This is my first attempt at harvesting commercial yeast and I think I've made a mistake.

I want to make a Two Hearted clone, so I figured I'd harvest some yeast from 3 bottles of Midwestern Pale Ale that I have. I guess my mind went on autopilot when I was making the starter because I used my normal measurements (1/2 cup DME & 2 cups of water).

Is the gravity of my starter too high?

I poured the dregs from 3 bottles last night. Its sitting on my stir plate, no activity. I'm not so concerned about no activity at this point, it's too early. However if my gravity is too high and I'm going to end up stressing the yeast to the point they're not what I want, I might as well dump it now and start over rather than waiting.

That should have a pretty good chance of being fine. I usually do first steps at 1.040, I just keep the volume really small. The concern there is more to do with how quickly the yeasy in the bottles can form a dominant culture. Multiple bottles should help with that, but it may take a few days to get active again.

Riot's suggestion is on the money. The volume of unfermented wort should be kept small when attempting to restart the sediment from a bottle of bottle-condition beer. I have used different volumes in the past, but I currently use 40mls of autoclaved (pressure-cooked) 1.030 wort to start a culture from a bottle. I crop the sediment by leaving about 10mls of beer in the bottle, which is enough beer to swirl the sediment into solution while avoiding the tiny starter becoming mostly beer. One should also remember to flame or wipe the lip of the bottle before decanting the beer and before pouring the swirled sediment to minimize/eliminate wild microflora pickup. It's not fail safe, but anything to that one can do to minimize wild microflora pickup during the transfer is a good thing.

By the way, if you do not own one, a small electronic gram scale can be purchased for under $10.00. Weighing DME allows one to hit a target specific gravity much easier than using dry measurements. A 1.040 starter is 10% malt by weight per volume. For example, a 1L starter containing 100 grams of DME has an approximate specific gravity of 1.040. A 1L starter containing 75 grams of DME has an approximate specific gravity of 1.030. The key word is approximate because DME is hygroscopic, that is, it has a tendency to absorb moisture, which will affect measurements.