I'd choose a couple options with sour, don't put all your eggs in one basket.
If you're just looking for smoke I would say fem or regs don't matter too much. You'd be more likely to find a plant more like the mom in a cross vs an s1. You can find good shit in s1's for sure but they're better off being used as a breeding tool than a way to find a keeper. If you find a plant that's almost identical to the mom in s1s you're theoretically going to have less genetic variability in the next generation of whatever you cross it to.
As I said before you're more likely to find something really close to the mom in a cross. What it's crossed to is the question.
I dunno if dynamite diesel is still available at GPS, that's definitely a solid option.
If you can wait for Karma's you wouldn't be completely disappointed. I keep missing the drops.
Top Dawg has gotta have a handle on his sour lines. He has a sour dubb x sour diesel bx.
Shoreline has a BX2 that I'm sure is good. I know he's got the real deal and would bet he's got enough experience with the plant to do those BX2s justice.
Swamp Boys have Juggernaut, ECSD x (GMO x TK/Skunk), would be a more modern version of a sour line if you bred it that way. Better density, resin coverage, more body and for sure more lengthy effects.
Harry Palms at Bloom Seed Co has a Sour Garlic Cookies BX that would be nice if you're looking for a more tame plant with a shorter flowering time.
Souvenir Seed Co has a couple of really cool diesel crosses that, while pricy, are sure to scratch that itch. There's Death Coast Diesel which is basically a fem BX2 with Death Star being the original mother. He also has Rubber City which is Sensi Star x Sour D, the genetics of Death Star. He's pretty sure its the same Sensi Star used in Death Star so that's gotta be dope. I have a few packs of the Death Coast Diesel, I honestly expect them to be more useful than s1s could dream of being.
I'm editing in a recommendation of Useful's Chocolate Diesel s1s or his reg line. I've grown his s1s, they're awesome. I like chocolate diesel more than ECSD when it comes down to it. More complete high, super similar taste - including the unmistakable ECSD aftertaste, better plant in almost every way that ECSD lacks without taking too much away from what makes ECSD so awesome as a plant. I can't believe that this slipped my mind.
Everything I've mentioned so far has been very close to the sour/chem profile but I would be remiss if I didn't recommend you try sour d crossed to a fruity or purple strain of some sort. I think that sour combines particularly well with the darker fruit/berry/grape type strains. Most people try to cross it to a citrus/tropical plant and for the most part those just muddy the diesel out of it.
I'm gonna message you a few options currently available.
