There are many variations of the Uncial hand. One thing that is important to remember is that it is closely associated with spiritual subject matter, relating to either blessings or curses. The movie "the Crow" uses "MAEL" for the main title. It is about a young rock musician who was murdered and is resurrected as a vengeful superhero. The treatment is very loose, and hurried, but this use is in keeping with the ecclesiastical origins of this writing style.
The monastic scribes of Ireland and Scotland developed this style of writing to a high degree, and kept using the style long after other parts of europe adopted other styles. Further rounding of the letters in the 8th - 9th C gave us a more compact letter called "half uncial". This style of writing is often used to evoke the Celtic culture.
The Stonehenge font is an example of a very delicate Celtic uncial, and half uncial, with constructed serifs. In medieval writing, the capital and small letters would not be used together.
Some excellent fonts for representing Celtic Culture are Gaeilge 1 and 2. The fonts are placed in the public domain by the author, and include MS Word macros for rendering the Irish language.
The font Gaeilge 1 was originally developed by Pádraig McCarthy in 1993. Gaeilge2 is an updated version, dated 1996, by Padraig McCarthy and Nikita Vsesvetskii
Celtic scribes were also Influenced by their Northern neighbors, the Norse. They had their own form of writing, called runes. These letters were usually carved in wood with a simple knife, and were also used for carving in stone. They were composed of straight lines, and were narrower than they were wide. the Runic alpabets used their own series of letters, and while they were probably influenced by Greek and Roman writing, Runes represented a separate alphabet
The Celtic scribes used angular letters inspired by these runes for decorative initials and chapter headings.
These letters are not easy to read, and I believe that is part of their intent, to slow the reader down, at the beginning of an important passage. The tall, angular forms provide a strong contrast to the rounded Half Uncial letters they would accompany.
For greater legibility, some Modern fonts with a Runic influence may be substituted for the Celtic runic capitals.
A variety of regional writing styles developed across Europe, before the Emporer Charlemagne ordered his chief scribe, Alcuin of York to do devise a script which would become the standard for writing across the Empire. The resulting script, Carolingian Minuscule was a very compact half uncial, with long ascenders and descenders, with a club shaped serif on the ascenders.
Extending the ascenders and descenders in this way gave words recognizable shapes, where the same word in all capitals blurs more quickly in a featureless block. This is an important factor to remember in modern typography as well. A few words in all caps are good for making a reader slow down and pay attention, but if they want to get on with the story, lower case letters are much more readable. For a graphic demonstration, look at the image below. I have reduced the size of the capitals to be comparable to the small letters. The minuscule writing remains more readable, even when blurred.