Who is the ghostly ‘WR’ in the First Commonplace book?

Who was the ‘WR’ who wrote annotations in Burns’s first Commonplace Book, annotations addressed directly to the poet? Clearly not to be confused with the annotation of later commentators like Syme, Currie and Roscoe, who gutted it after the poet’s death for material to publish in Currie’s 1800 edition of the poet’s Works. I was initially confused by this and assumed that ‘WR’ was William Roscoe, but now I m convinced that’s not the case. There’s good internal evidence that these annotations were written in 1786 prior to the publication of the Kilmarnock Poems, and that Burns had requested ‘WR’ to assist him in the selection of appropriate material. Earlier commentators have suggested that the initials stand for ‘William Ronald’, one of three men of that name in Burns’s Ayrshire circle: the gaudman at Lochlie Farm, a tobacconist in Mauchline, or the laird of the Bennals, a farm near Tarbolton whose daughters were admired by Burns and his brother Gilbert. But would the poet have entrusted such an important task to any of these men, none of whom seem to possess the literary judgement that’s so evident in the annotations as they stand on the page? So please, can anyone suggest another candidate? Who is the ghostly ‘WR’ in the First Commonplace book?

— Nigel Leask