I observed these three pairs last night with a 6" f/8 apo, using a 8.8mm ES ep on the first one (2321) giving 138x, and the other two using a 7mm TV Delite giving 173x.
They weren't difficult, but simply beautiful little pairs to observe.
STF2321 PA=191 Sep=6.7" m1=8.49 m2=9.61
STF2324 PA=149 Sep=2.4 m1=9.04 m2=9.37
STF2347 PA=259 Sep=3.4 m1=8.07 m2=9.75