In a perfect world yes a knowledgable instructor or even better a factory course would be the best. However I don't think I have to tell you how the real world works, I've been flying AS350s for 7 years now (Never flown dual hydraulics), no company ever offered a factory course and I sure was never able to afford it myself (23000$ from Airbus back in 2017), all the instructors I've flown with where line pilots that knew probably same thing I knew or less but flew the aircraft daily.