What size should I get my DTF design?

In regards to DTF sizes, we normally suggest the following:

Babygrow upto kids 5-6 we'd suggest 5" wide ( max 6" high)
6-7 kids upto XL adults we'd   suggest  8" wide ( max 12" high)
XL+ upwardswe'd  suggest 10" ( max 14" high) 

Now due to certain shapes, some designs may be longer in height than they are in length so as you can see I've given the cut off hight beside each size. In some cases by making a design that is longer in height, if you were to have it 8" it could be 15+" tall and may not fit on the tshirt, so in certain scenarios, we would go off the maximum height. I hope that makese sense.