Ear molds vs tubes with domes

Our son, age 5 wears phonak eXtra 211AZ bilaterally, was fitted at age 3 year 10 months, he does well with them.

I have never been happy with how his molds fit and look, his ears are atypical. The cavum conchae is convex instead of concave (the part of the ear if you were to put your finger in your ear and balance your finger there)- the bowl of the concha, it is the part where the the ear mold sits.

His ear molds have always been oversized and they seem to stick out further than his ears themselves, almost like there is an extra lip… up to now function has outweighed appearance. he has started school now and I would like to see his earmolds be better fitted to him.

With the Phonak aids he has, the user guide shows 3 options, with earmold, with Fit’nGo slim tube and with Fit’nGo standard tube.

I was told that he could not use the domes because the level/degree of hearing loss he has… Is that true? Does anyone know if the domes/the tubes can only be used with certain amounts of hearing loss? To me it just does not make sense how the part of the hearing aid past the sound outlet is dictated by the degree of loss.

Looking at the pictures, there is a retention tail past the actual part of the dome/or tube, that retention tube just sits in the bowl of the concha. and looks to be the part that you would tug on to remove the dome/tube from the ear with. Is the retention tail a part that must be there for this system to work, or is it only an aid to help remove it from the ear? can it just be left off?

I also see a picture describing how closed domes work, the one that has 2 fins on it, compared to the dome which is a solid dome.

Does anyone use the smaller domes or tubes and not the earmolds and how do they compare in actual ware? Easier/harder to get bumped and not fit? Because there is such a small part holding it in your ear is the BTE part of aid more likely to fall off? How would you feel being a rough tough tumble 5 year old on a playground, are they going to fall off?