ic þankie ēow.
I have a further query: we've got Ææ, Ðð, Þþ all sorted, but how important are the diacritics? I've seen Anglo-Saxon texts both with and without macrons, and the dot over the c and g are new to me, but logical for pronunciation guidance.
I've worked out another method by going to
http://icelandic.typeit.org/ for ð, þ and æ, and then composing in the box, and then switching between the languages in the left-hand column there to get further letters. The Maori keyboard
http://maori.typeit.org/ conveniently has the macrons ready to click for ā, ē, ī, ō, ū, but not for æsc.
The ǣ in particular takes a couple of clicks, by switching to the IPA full keyboard
http://ipa.typeit.org/full/, selecting more symbols to open up the full range of symbols, selecting the macron, then selecting æ.
I still haven't worked out how to do the C dot or G dot there; but are there other symbols I need to look out for (ignoring ƿ, as I could use modern W, and ᵹ, using modern G)?