Area-51m R2, possible ram configurations?

Hi, I would like to know if to my Area-51m R2 with 2 16Gb (32Gb) 2933Mhz ram banks I can add another 2 (I was thinking of Crucial's Ballistix) always 16 to get a total of 64Gb. The doubt arises when I would like to mount not other 2 banks at 2933Mhz but at 3200Mhz. From what I understand the machine can work maximum either with 64Gb at 2933Mhz or with 32Gb at 3200Mhz via XMP.

What I fear is that by mounting these other 2 banks in addition, the system detects me only the new ones at 3200 or all 4 at base frequencies (2133Mhz if I'm not mistaken) failing to set the correct XMP to any of the 4.

Briefly, my intention would be to be able to choose between 2 configurations at will:

- 32Gb at 3200Mhz enabling from the system (with XMP profile?) Only the 2 new Crucials (Gaming)

- 64Gb at 2933Mhz (limiting the speed of the Crucials with another XMP profile) using all 4 banks (Rendering, if the 32, as sometimes happens to me, were not enough)

Can I have this choice while keeping the 2 new desks always mounted in the PC? Or, if I want 64gb to have no problems, do I have to buy the new 2933Mhz banks directly, giving up the possibility of 32 to 3200?

I hope I was clear enough, I send a greeting to the whole community wishing you a good day!