Westra lage wegas rehtas... or Tolkien's Proto-Germanic text

I have had some guesses concernng the Tolkien's words: 

»Westra lage wegas rehtas, nu isti sa wraithas« 

These words can be found in two sources: in "The Lost Road" (HoMe V, p. 43) and "The Notion Club Papers" (HoMe IX, p. 243, 287, 304), in the form:

»westra lage wegas rehtas, wraikwas nu isti«

In this last story Prof. Alwin Arundel Loudham, B.N.C. ("chiefly interested in Anglo-Saxon, Icelandic and Comparative Philology", p. 159) provides us also with the Old English version of this sentence:

»westerweg wæs rihtweg, wóh is núþa«,

and with its translation: 'a straight way lay westward, now it is bent' (or like in The Lost Road: 'a straight road lay westward, now it is bent').

Tolkien wrote that Westra lage wegas rehtas... was in "a very old form of Germanic; pre-runic" (HoMe V, p. 43) and "like very ancient form of Germanic" (HoMe IX, p. 243)

I have asked a specialist: Nelson Goering wrote to me: 

It's basically Proto-Germanic (what Tolkien would have called Common Germanic or the like). It's really quite archaic. The final -e of lage and the -i of isti are Indo-European final vowels that have been lost in basically all Germanic dialects, even Early Runic (though the final -i's are in the process of being lost there). One odd thing is that he uses final -as where most people reconstruct *-az. So either Tolkien had opinions on this, or he was something so old that Verner's Law *-az had not yet become the universal form. So neither Old English, nor Ingvaeonic. In both of those varieties, for instance, the final -as's would have been entirely lost. In Ingvaeonic, I might go with something like *west lag weg reht, nu ist sa wraiþ, and in Mercian Old English this would be west læġ weġ reht, nu is se wrāþ (keeping the word order the same).

It is how Karen W. Fonstad showed The Silmarillion's Earth in her atlas

The Straight Road