The primitive form ✶srawā was introduced in notes associated with the essay Athrabeth Finrod ah Andreth from around 1959, where it served as the basis for Q. hröa/S. rhaw “body” (MR/350). The Quenya word hröa served as a replacement for Q. hrondo “body” < √SRON “flesh, substance, matter” in the essay Of Death and the Severance of Fëa and Hrondo also from the late 1950s (MR/217, 231 note #26). It is not clear whether √SRAW was intended only to replace the sense “flesh” from √SRON or the sense “matter” as well: in an essay on the motivations of Sauron and Melkor Tolkien glossed Q. hröa as “flesh” but indicated it could be applied to the physical matter of Arda, a notion for which Tolkien elsewhere used the term Q. hrón, later revised to orma and then Q. erma (MR/399, 406 note #2).
Regardless, the connection to “flesh“ survived in later writings: primitive ✶srawā > Q. hröa “body” reappeared in notes discussing Q. órë from 1968 (VT41/14), the form ✶srā “flesh” > S. rhaw appeared as an example of a primitive monosyllabic noun in notes associated with Eldarin Hands, Fingers and Numerals from the late 1960s where Tolkien said it had probably lost a final -w in ancient times (VT47/12), and ✶srā “body” appeared in a list of monosyllabic nouns from 1968 again with signs of lost -w via the extended form ✶srawa (VT47/35).
√SRAW “flesh, body” may itself be a reemergence of some similar early roots. In the Qenya Lexicon of the 1910s Tolkien had ᴱ√SṚKṚ “fat” with derivatives like ᴱQ. sarko “flesh, living flesh, body” and ᴱQ. sarqa “fleshy” (QL/86). The words ᴱQ. hara “flesh-meat” and ᴱQ. haranwa “fleshly, carnal” were given without a root (QL/39) and were probably connected to words like G. hara “flesh meat, meat” and G. harc “flesh (on a living body)” from contemporaneous Gnomish Lexicon (GL/48). These might somehow be connected to ᴱ√SṚKṚ or could instead represent an otherwise unattested root like ✱ᴱ√HARA.
The unglossed root ᴹ√RAG appeared in The Etymologies with the derivative ᴹ✶ragnā > N. rhaen “crooked” (Ety/RAG). A similar root √SRA-G “awry” appeared in Definitive Linguistic Notes (DLN) from 1959 as a replacement/reversal of the root √SRA, SRAYA “easy, pliant, moving with ease”, with the sense “easy” apparently transferred to √AÞA (PE17/172). The page where √SRA-G initially appeared was ultimately rejected, but √SRAG appeared again in DLN with variant √SRAK among a list of roots all meaning “hard, difficult” (PE17/154). In the later list it had derivatives like Q. hraia “awkward, difficult”, Q. hranga “awkward, hard” and Q. hranga- “thwart”, along with S. rhanc “awkward, hard” derived from the variant √SRAK (PE17/154). In another set of notes from 1959 Tolkien mentioned the root √SRĀ or √SRAGA “awkward, very difficult” with derivatives Q. hrai/Q. hranga “stiff, awkward, difficult” (PE17/185).
Neo-Eldarin: For purposes of Neo-Eldarin, I would transferred 1930s N. rhaen “crooked” to √SRAG “awkward, difficult”.