Honestly I was seeing that half a mat for 10U kids were running out of real estate when trying to do stand ups and even finishing takedowns. Probably not logistical but if you could compare the number of restarts to other age group and size of mat they were using and if found certain groups excessive compared to other groups then mathematically you would know you need to increase the mat surface for certain age groups.
I personally love seeing kids on a full mat, at least 10U and above