I think chances of getting a match to Classic Plus are really slim, as I have never heard of this happen. But they match a variety of cards to Elite. So you should try for a match to Elite.
Normally for a status match request, you would send in a photo of your card. But in your case I would try my luck without the picture of the card, because I presume it has a *S logo on it, which is a red flag that your status is not equivalent to Elite. If the TK employee approving your status match doesn't already know that Altitude Elite 35K is lower than *G, he/she may match you to Elite. It does require a bit of attention to realize that Elite 35K is *S while Elite 50K is *G.
Just send in an email saying that your status is equivalent to M&S Elite and request a match, attach a screenshot of your Altitude 35K account as proof.
You might go as far as photoshopping the card photo to show the *G logo instead of *S and send that in. But that would be fraud, so I would advise against it.