Tefillin for a tall or thin animal

Hello. As far as I understand, there is no difference in principle and halakhically both are permitted. However, in the past, they did not know how to process thin meat (it is very difficult, and therefore sometimes the cavities are small and it is difficult to compress the meat), and thin meat is torn and sometimes made of several patches (therefore, coarse is preferable). What happens in practice? Can you trust that there are no tears in a single copy and that everything is fine? You should ask a knowledgeable copywriter. If they tell you that they do, I would buy a single copy. After you've considered these points, if you come to the conclusion that a rough behemoth is better, I don't know how to recommend what to do with a RT. It's your decision what you prefer and how important it is to you to save money. Congratulations and much happiness.