Minimum Text Size for outlining with 40 Weight Thread on Small Text

Expert Small Text Digitizing Tips for having a single outline

TLDR Problem: With Small Text outlines: especially when the design is going on CAPS, the risk is to consider telling the customer that a design element of outline is constrained.

The possibilities include:

(Desirable) Alter the layout "slightly" and deliver embroidery on 40 weight threads.
Create the outline in SPECIALIZED 60 weight or 75 weight threads (Madeira, RA, Isacord, Gunold and all major carriers sell them)
(Least Desirable) Create the outline in a run stitch.
The other option is to drop the outline completely.

Special Caveats to consider:

TRICKY aphabets that contain HOLES like "A", "P", "B", "O", and even "E", "F"
Presence of Lower case Alphabets
Font Type, including Calligraphy and Monograms
Presence of underlying elements like fill stitches
Arch / Circular / Applique and Rockers
Gradients, Distressed effects and Patterns within the text

The above requirements enforce additional constraints on the outline's ability to be created with a 40 denier aka 40 weight embroidery digitizing thread (on Poly Neon, Matte, Rayon, Wool and specialty Luminescent threads).

This is especially when the design is going on CAPS, the risk is to consider telling the customer that a design element of outline is constrained.
Lets split it up based on the fonts. First, here are the images to support the discussion and the sizing information by Quality Small Text Digitizer.

Input photograph and not vector (aka raster) Artwork:

Small Text with Thin Black Outline original Artwork before Quality Small Text RUSH Digitizing by Abcoln

Here is the image at 7.5 mm for BLOCK font:

Small Text with Outline Aufman Associates with Embroidered Run Stitch outline for 7 and a half mm tall text

Here is the image at 8 mm for (still the same) BLOCK font, and yet the quality is still not enough:

Small Text with Outline Aufman Associates with Embroidered 40 Denier Thread outline for 8 mm tall text

Here is the final option at 7.5 mm with the outline removed (still the same) BLOCK font

Small Text with Outline Aufman Associates with Embroidered for 7 and a half mm tall text with outline removed

Sign Me Up. I challenge Abcoln to WOW me.

Here are the final recommendations:

For BLOCK font: Preference is to use 10mm height (For a 40 weight thread). 9 or 8 mm height is acceptable in situations where there is no "A", "E", "P", "B",... For BLOCK font: Preference is to use 9mm height (For a 60 weight thread). 8 or 7 mm height is acceptable in situations where there is no "A", "E", "P", "B",... For SERIF and other fonts: Preference is to use an additional 2 mm height