It’s all in perek 2 of hilchos talmud torah, where he says how much we have to toil to know kol hatorah kulah, which he says is mikrah mishnah and talmud…once a person knows the material, he’s supposed to spend the rest of his time on svara, lashos and terutzim, what we call “lomdus”
במה דברים אמורים בתחלת תלמודו של אדם אבל כשיגדיל בחכמה
וירבה בה במאד ולא יהיה צריך לא ללמוד תורה שבכתב ולא לעסוק תמיד בתורה שבע”פ מפני שכבר חזר על לימודו פעמים רבות מאד עד שנחקק היטב בזכרונו כל התורה שבכתב ושבע”פ כולה אזי יקרא בעתים מזומנים תורה שבכתב ודברי תורה שבע”פ כדי שלא ישכח דבר מדיני התורה ויפנה כל ימיו לעיון התלמוד לסבור סברות בהלכות ולפלפל בהן בקושיות ופירוקים לירד לעומק הסברות וטעמי ההלכות להבין דבר מתוך דבר ולדמות דבר לדבר ולחדש חידושי הלכות רבות לפי רוחב שיש בלבו וישוב דעתו כמו שאמרו ליגמר אינש והדר ליסבר.
He’s talking about someone who was not taught, and this is how he is supposed to teach himself. Someone who has a chinuch, is supposed to go from mikrah, to mishnah, to gemara, like chazal say in avos. Then he says to be meshalesh, but not in equal times, because he says gemara is a lot harder than mikrah.
Nowhere in any of the prescribed times or limudim is there any mention of chasidus. Not one. The only time he mentions it is when he says to learn kabalah-based mussar seforim, but he clearly says that it’s a side thing.
As for the rashab – alecha lehavi raya. If he in fact did that, then fine; you’d also have to ask a few questions once we verify the story:
Did all Lubavitcher boys go to this Yeshiva, or was it like elsewhere in Europe, where only yechidim did, and if so, what was bis reason – and why did he have to institute it? When he made the change, what was before, what caused it, and what happened afterwards? Then we can see if there’s any way of applying what he may have done to our times.
Because when i see chabad boys learnihg chasidus for hours, all i see is that it makes them confused about basic yiddishkeit and way too conceptual, while influencing their way of thinking halachikally. They also don’t really know what they’re talking about, because if you ask enough times “what does ain sof mean,” and proceed to ask what the definition is of the words they use to describe it, you’ll see that they’re not actually knowledgeable about kabalah….since it’s, after all, kabalah!