The phrase "right scale" means finding the appropriate or suitable size or level for something. It refers to correctly matching the magnitude, quantity, or extent of an action, object, or situation to ensure a better fit or balance. Full definition
The study includes a left - right scale of voter opinion from five questions on attitudes towards things like redistribution of wealth. (theconversation.com)
Thordarson et al. (2004) described the contents of Just Right scale as doing things exactly right, following strict routines, repeating, me - morizing, and concern with being perfect, and feeling compelled to count. (scirp.org)
Cameron's score on the left right scale (where -100 is very left wing and +100 is very right wing) is +48, compared to Michael Howard's score in 2005 of +52. (ukpollingreport.co.uk)