Hi and welcome :D
I'm not sure I'm going to be as helpful as 38th is imagining though :lol:
From my current experience, I think it's all going to depend on what the new build sounds like accoustically.
I've got a very bright and almost "hard" sounding 60s Roadworn. That sounded a little thin for my tastes with its original pickups (Tex Mex). I've got Irish Tours in there now, and they've beefed the tone up ever so slightly, but otherwise it hasn't changed a lot. Depending on how hard I hit it, it's capable of melodic with a bit of an edge to it. The main thing for me is that with ITs it's got a bit more "authority" to it's tones than before.
Another change I made recently is I swapped out the ceramic disk tone capacitor for a paper-in-oil (Vitamin Q, but I believe any make of PIO, including cheaper ones, would have the same effect). That was a quite a huge difference in this guitar. It mellowed some of the top end, making it sound more "vintage". It also lowered the overall output slightly so I was able to raise the pickups for a different "sweet spot" (making the tones a bit fuller again).
This guitar is pretty much my go-to strat sound now. For the way I play, it is so expressive, able to growl, punch and be more delicate as well (all on the guitar controls and varying my attack).
My other main strat is a CIJ Fender "62 re-issue" - this is where the Sultans have just gone in, and I'm having a bit of a love affair with it at the moment.
The CIJ, in comparison to the Roadworn, is a very warm sounding strat. The ITs were in here originally, for nearly two years. I loved it like that, but they sound a lot clearer in the Roadworn than they did in the CIJ.
What the Sultans are doing in the CIJ is a completely different story. They are warm and rounded sounding, with a "sweet" top end. They are seem clearer than the ITs did in the same guitar - but that might be my memory playing tricks. I'm still finding I'm struggling for "sparkley" top end with this guitar sometimes. I did actually put a PIO capacitor in at the same time as the Sultans, so next string change I shall switch back to ceramic disk to see where that takes us. Having said that, it sounds glorious, it encourages me to go for cleaner sounds than I usually do, just to hear that "strattiness" :D
I'm not sure how this helps you though... given my taste in strat sounds, I really ought to have a set of Mother Milk's by now, but I haven't, so I can't really compare...
Assuming your strat ends up with enough "body" in its accoustic sound, I suspect that Mother Milks is where you want to be. I understand they are the epitomy of "60s strat", with a fair bit of top end, that let the woody strat tones through.
I believe that, if the guitar is quite bright and hard sounding, like my Roadworn, that Apaches would round it out nicely to give classic strattiness... (if you were putting BKPs in that 70s strat, I think I'd recommend those - possibly 38th would as well - I suspect it would be a killer then)
I chose Sultans for my darker CIJ because I wanted to move away from the sound I was going for in the Roadworn. I thought Apaches might be too rounded in this guitar, and Sultans appear to be almost "Apaches plus a sweet extra top-end". Can't guarantee that this is actually what they are, but they've certainly come up with the tone I was dreaming of! :lol:
I wouldn't rule out Irish Tours either - bear in mind what they've done to my Roadworn, thickened it ever-so slightly. Some people have found ITs a little too "bright", a bit too much in the mids/upper-mids, giving them quite a gritty attack - but that's kind of what I like, I use the guitar tone a lot to tame it.
The other reason I wouldn't rule out ITs, is because of the Blackguards. If I was looking to take one strat and one tele out, and they had to be in the same "ball park" for power and tone, I'd take the IT and BG pair, or I'd take the Sultans and Yardbirds pair.
Sultans/Yardbirds - smoother, possibly more versatile, capable of more natural sweetness.
ITs/BGs - grittier and capable of more natural aggression.
My gut feeling is that the Mother's Milks will suit you down to the ground though :D
EDIT: I do actually think the Sultan's might be worth a punt too, and if I'd tried the Sultans in the Roadworn as well as the CIJ, I'd have a much better idea.
