I never attempt to use the hydrometer tube to take my sample. Typically by the time I'm ready to take a sample the fermentor has already been sealed up therefore it has 5+ psi on it. I usually open the sample port alot very quickly with a large container underneath and it will blast the dryhops out and from that point on it can be opened normally without the clogging. I Just need to be ready to close the valve quick because once it clears it comes out very quick. Cheers
Yeah, you'll only try to use your hydrometer tube under the sample valve one time.
I drain mine into a half-gallon plastic pitcher, first blasting it a bit to clear any trub. Then I'll fill about 4 ounces of beer into the pitcher, and transfer to the hydrometer tube.