Hey!
I wouldn't stick too rigidly to a 50-100 word limit unless the application specifically gives you one. The more important thing is making sure each entry gives you a clear picture of what you did, the skills you demonstrated and what you gained from the experience.
For shorter experiences, 50-100 words may be more than enough, whereas a more substantial role might justify a little more detail. I would prioritise relevance and quality over trying to hit a particular word count. If you have a word limit for the overall section, then I would also think about allocating more space to the experiences that are most relevant to the firm and the role
