nr 1 and 2 have no entry strokes at a's and e's - where present, the entry stroke is shorter than in nr 3 {it doesn't seem to start at the base line if I see well}
nr 1 and 2 have no loop at l's
nr 1 and 2 have a smaller first arch at m's and n's {whereas penmen make a point of having all arches with the same width in Copperplate}
nr 1 and 2 have the straight stroke of the p shorter on the top than nr 3
Is there any known reasons for these differences?
Different tools that lead to these differences or just different styles?
Firstly, I should say that I base all my Copperplate writing on the examples in The Universal Penman by George Bickham. This book is still in print and anyone interested in the script, shouldn't hesitate in getting a copy.
Where the rounded minuscule a c o e d g & q begin a word within text, there is no entry stroke. All other have a short entry stroke. I usually prefer an entry stroke from the baseline, but that's just my choice.
In The Universal Penman, 99% of ascenders are straight. There are a very few looped ones and this didn't become general practice until later. Both looped and straight versions can be used, even within the same text. In Engrosser's Script they are always looped.
The original 'n' and 'm' had smaller first arches. The use of same-width arches is a later manifestation and now seems to be the general rule. I prefer the earlier version which to my eye was more elegant.
In Engrosser's script the 'p' and 't' are longer. This may be due to the influence of Spencerian Script. Originally, they were shorter with the 't' crossed at the waist line.
There is one further difference between the drawn and written versions. The drawn versions (1) and (3) use secondary downstrokes on the loops of 'l' and 'e' for example, to produce little shades. Whist this is historically accurate, I prefer to keep the lettering flowing as handwriting, and omit these as shown in (2).
The same pen and nib is used for Roundhand and Engrosser's script.
Good questions - you are very observant.