Does a DearSD head look "proportional" on a SDC or SD body?

New Saki (SD-F-59) and Chiyo (SD-F-61) were SD10 standard models from several years back. The DearSD versions are special editions (more or less) that are just the regular SD10 sculpts on the shorter DearSD body (this is the case for all DearSD- they are all 1/3 scale sculpts that work on SD10/13/etc) The SD10 sculpts would NOT be proportional on SDC bodies.
Neo Angel Den - Volks FCS - 60cm SD FCS - Head Molds
Neo Angel Den - Volks FCS - 60cm SD FCS - Head Molds
You can:
- Put the DearSD heads on an SD10/13 body
- Wait for an old standard model (note: single-jointed elbows) to pop up
- Order via Full Choice System when available (or find one secondhand)
Saki and Chiyo are currently available in SDM (1/4) size as standard models. These are sized down versions of the SD girl sculpts. If you're after SDC body in particular, this body hasn't been used in a while so you may have trouble finding a good resin match. SDM is the main 1/4 scale Super Dollfie body in use.
SDM女の子 ちよ | ボークス公式 ドルフィーオンラインストア
SDM Girl Saki | VOLKS Official Dollfie Online Store

 

New As OneMoreLight said, Chiyo and Saki were originally intended for SD10 bodies as Standards. DearSDs use SD10+ size heads to give them the "big baby" look which was trendy at a point in time but is less popular now. All DearSD heads will work on SD bodies, although because a lot of them are chosen for big eye cute factor, they might look odd on on SDGr or larger bodies.

SDCs are in kind of a weird space: they're Volks's brief foray into a more mature mini size. Volks describes as sharing head size with their Yo-SD line, who typically have 6-7" heads. I don't think a head from a DearSD would look good on an SDC body, as they're designed to be opposite ends of the 1/4 scale: giant baby vs more mature.

In terms of accessibility of bodies, Volks's SD10/13 bodies are widely available secondhand and very affordable. Some hobbyists only buy Volks dolls for the heads and offload the bodies cheaply to be rid of them (I personally like Volks bodies).
The SDC line is less available secondhand, especially as there hasn't been a new SDC release in several years: I was surprised to see one in the One Offs last year. The SDC bodies are also not as strong posers, especially the girl body (I have a very floppy SDC boy who is going to need new elastic and wire to stand well).

For reference: Nico (SD-F-82) and Saki (SD-F-59), both on SD10 bodies

Bonus under spoiler: Old F-07, released on DearSD body as Nayu/Nao, SD13 body. This is one of the biggest Volks heads I've seen (along with F-01 and F-32) and she still looks fine on the larger body to me

Spoiler: Images under cut