The compounding pharmacy I used to buy from seemed to like standardizing on a 50 unit shot. I tend to prefer 10-20 units for most peps. One thing to keep in mind is that the larger the shot, the less loss there will be due to mistakes or process.
That is, losing 1 unit of a 5 unit shot is a bigger deal than losing 1 unit of a 40 unit shot. Ultimately, it comes down to whatever you’re most comfortable with as long as your math is right and you are dosing correctly.
GLP-1’s are one peptide where you do not want to calculate incorrectly.