"Lupin III Part 6"...just saying the title out loud is going to confuse the vast majority of people. To Lupin's credit, at least their titling sequence makes more sense than most anime series. For example, DragonBall, Z, GT, Super, Diama, Heroes, with Lupin III, anyone can tell what order to watch the series in. Lupin III is a bizarre franchise, it has been going on for over 50 years, but still doesn't seem to have any major following. Those that are in the know, form a devoted fan base, and for good reason. The reason why these shows and movies are able to keep going is based on the charm of these characters. Lupin, Jigen, Goemon, Fujiko and Inspector Zenigata are the anchors that keep this ever-changing world grounded. You could put these characters in just about any setting and it would be entertaining.
I haven't seen EVERY Lupin III property, doing that would take over a year of constant screentime. But I have seen a dozen of the movies, and episodes of Part 2. "Part 2" has a wild English dub.
"Part 6" takes the character a bit more serious than some, but still maintains that signature Lupin wit. The series is strange in its format. It is a serialized show where one episode builds off the next, but it is roughly split into 2 halves. One focuses on Sherlock Holmes, (not Sherlock Hound), and the other focuses on a different conflict. The first 3 episodes of both halves will follow the main story, but then they'll take a 3-episode detour going on random episodic adventures. Then for the final 2-3 they will return to the main story. Keep that in mind as you watch the series.
Despite the odd format for the odd series, it is Lupin at his very best. It is just the right level of serious and funny. The characters are all true to what has made them last for half a century. If you are a fan of this very specific series, than I will give you this super specific recommendation.