Hey @Vesti, “Hindu Kush” is a fairly broad term that could encompass several of those strains. It only really means a strain from the Hindu Kush mountain region, which encompasses much of Eastern Afghanistan to Northern Pakistan and Eastern India.
From my personal experience, I would only grow Deep Chunk or PTK to hybridize. They have some good qualities for making hybrids, and very stable pedigree with some good traits for breeding, but there are other “Hindu Kush” strains that I would usually prefer for growing and smoking. I think the MLI seems like a good option if you can find a good one (I haven’t grown it yet). And there are tons of great Hindu Kush heirlooms around. Even World of Seeds, which some people like to call World of Shit has a decent Hindu Kush.
I would probably not choose Sensi or Mr Nice as a first choice for those, myself. And also some of the lowland Afghans might meet your criteria. Here’s some that I have either grown, or that interest me, that are not hard to find:
Royal Queen Seeds - Special Kush #1
Seedsman - Narkush
Black Kandahar / Black Afghani
Bodhi - Cherry Queen (though not a very narcotic variety)
New420guy - Mazar-i-Sharif
New420guy - Post Traumatic Purple
Indian Landrace Exchange - Hindu Kush (might be a little more “wild” than heirlooms though)
Afghan Selections - Anything, but also might be more wild
Aficionados Colorado - Hindu Kush