distance impact intensity of light hitting the canopy, so absolutely it does impact plant height, relative to genetics.
internode length - the distance of stem between two growth nodes - is exactly how you assess it.
runts will have short spacing no matter what... Variation in normal plants exists too.. so you can't expect every plant to have the exact same reaction to your light intensity even if the light is exactly the same each time. Some plants are shorter than others, they often branch more -- similar amount of growth occuring over time, but distributed differently.
a bushy plant will always be bushy unless you trim it to be otherwise. e.g. a "red" heavy light may promot less axillary growth and more height, but it will never drastically change a genetically bushy plant. The effect is not noticeable with the eye even if it has measurable effect that is statistically significant.