A fascinating question. My "ear" tells me "tall heavy girl". But why? There is an adjective order rule of sorts in English, but, as you note, these are both adjectives of size. I'm going to guess that "tall heavy girl" has balance in its favor - the monosyllabic words are bookending the two-syllable word, so it rolls off the tongue more easily.

Adjectives should follow a specific order, unless you are trying to emphasise one in particular. In this case "tall" - a size - should come before "heavy" - a physical quality. Here's a good summary: https://dictionary.cambridge.org/grammar/british-grammar/adjectives-order

Adjectives should follow a specific order, unless you are trying to emphasise one in particular. In this case "tall" - a size - should come before "heavy" - a physical quality.

In agreement about adjective order that others have mentioned. However, size is divided into height and weight, and height comes before weight.