Over-dilution: when your dose falls below one readable graduation

Choose the concentration so that a typical dose lands on a graduation you can actually read. A dose that falls between two marks on a 1 mL barrel is a dose you will get wrong sooner or later.

I am not the right person to answer the follow-up to this.

On post #4 — agreed on the reasoning, with one qualification.

Distinguishing three things in the over-dilution discussion that keep getting used interchangeably: the observation, the proposed mechanism, and the recommendation that gets attached to both.

This follows post #6 rather than contradicting it.

Over-dilution: if your target dose is 0.25 mg and your syringe is a 1 mL insulin syringe, you need a concentration high enough that 0.25 mg fits on the scale. A 0.25 mg/mL solution requires drawing the entire 1 mL syringe — not readable. A 5 mg/mL solution requires drawing 50 μL — also not practical on an insulin syringe.

The confident version of this sentence would be wrong, so here is the hedged one.

Adding what did not work for me on over-dilution, since the failures never get written up and they are half the useful information.

No disagreement from me. Posting only so the question does not look ignored.