so what should I say about that now?
Compared to OEM and HML.
"German spec alloy steel". That says nothing at all about the quality of the material.
Not everything that comes from Germany is good. Once you have a certificate that describes the quality of the material, the same material from, for example, France is also perfect.
And then you also have to indicate what material you use.
HML uses 18CrNiMo7-6 for those sets, which is the standard for hardened sets.
Measuring tooth thickness with a digital caliper ?? I don't think an engineer measures gears like that. A child can understand that if you mill fewer teeth in a certain diameter wheel, the thickness thereof increases. 21/5 gives an even thicker tooth. That does not mean anything about the strength of a tooth. The type of tooth is. Gleason, compared to Klingelnberg, has the disadvantage that Gleason has a smaller tooth foot radius and therefore succumbs faster to tooth fracture.
In addition, the geometry over the tooth length at Gleason is a "circular arc".
At Klingelnberg this is an "Epicycloid", which makes the Klingelnberg system less susceptible to installation errors and house deformation under load.
If you are going to calculate with equivalent sets: Klingelnberg vs Gleason, Klingelnberg will be the strongest choice according to the calculation modules.
About the transmission ratio.
The cars with a 7-31 ratio will accelerate faster and you will lose your top speed.
At the same speed, the car will also go higher in revs, which is less comfortable.
All the best and good luck.