From a DIL's point of view, and seeing my mum as MIL to her son's daughter, you're always going to have a bit of a battle if you see the prospective DIL as a rival for your affections. Both DIL and DS will sense this and will resent it.
My DH really isn't very fond of his mum, despite the fact that she's an affectionate old bird who loves him madly. She made the mistake of smothering him when he was younger, so he couldn't wait to get from under her wings when he was in his twenties.
Now, he sees her as little as possible. She still drives him nuts by wanting to know every little thing he does and every place he goes. His sister, who's in her 50's, now fulfills that brief, almost living with MIL and rarely out of her pocket.
In terms of their current replationship, our DD provides the glue between the members of his family and there's no real warmth between DH, his mum and his sister at all. I used to find it a bit sad, but now, I'm similarly disillusioned with his know-it-all, control-freak mum.
My mum, in contrast, is quite hands off...almost to the point where it constitutes abuse LOL! Yet I love my mum madly and do anything I can to see her regularly. Go figure!
My mums son-in-laws think she's the perfect MIL. Hands off, supportive when needed, but generally, not very interfering.
My mum's DIL thinks she's a harridan. I can't figure out why, but it's an unavoidable truth.
So Mavornia.... I hope you manage to pull off that rare thing of getting a good relationship with your future DIL (or his same sex partner, if that happens to happen). I personally think you'll be in the minority if that happens, judging from familial experience and anecdoctal stuff from friends too.
Brainwashing may seem a good idea now, but long term? It might just backfire on you!