Thank you for this Ask! I need to answer a lil carefully again. The things I’m about to say mostly reflect my own decision-making process and my opinion. I would not want to make cosplayers feel uncomfortable ^^;;. I like cosplay and when anime conventions used to be a real thing, I did attend them while wearing a costume. I also like the Touhou franchise a lot. So, the cosplay outfits that I have include Utsuho and Miko ^^. The character designs of these girls are so cute! 

Choosing which cosplay outfit to purchase (or make, if you’re into that) is kinda complex because it can be quite costly. You need to feel comfortable wearing it, otherwise it’s a waste. By comfortable, I mean that (to me) you shouldn’t feel like the outfit doesn’t fit your body type. You shouldn’t feel embarrassed. Besides BMI, there’s a lot of stuff that you can’t really control; your shoulder width, waist/hips/thighs circumference, body length.. You can see what my body is like in my pictures; I am a fairly average Dutchy, though my legs are a little muscled due to cycling. To me, thereby I shouldn’t cosplay characters which are supposed to be small or child-like. Nor should I cosplay tall characters or muscled men xD. 

Regarding the three Touhou girls you mentioned specifically. I feel that at 1M75 I’m too tall to be Chen (or any child-like character for that matter). Sanae and Aya, I’ve not thought much about these girls. So far there’s no connection between me and these characters. I do want to purchase a new cosplay outfit at some point, but I was kinda looking at Gawr Gura rather than Touhou XD. This shark v-tuber has gotten way too popular, and I approve of sharks