Thanks again for the app and the source code. I began thinking about having a look at the source code, but on a whim I decided to get as familiar with the different options as possible. Discovered that Xt9 in Swedish on the keypad makes some odd errors, missing suggesting very common words that otherwise show up on Xt9 on the keyboard and the phonepad. Phonepad works excellently with Xt9 in Swedish, but the suggestion list gets longer (naturally with 3 possible character combinations for each key press).
The shocker was how fast I was able to type with relatively few errors with Xt9 on the keyboard in portait orientation (!). I started off carefully, hitting the back button and groaning every time I made a mistype - took ages, was what I expected. Then by chance I looked at the screen and the word I wanted was suggested, and just to the left was what I actually typed with two hideous typos. Got me thinking. Then began typing as if I just expected the phone to know what I wanted. Discovered that at an almost computer keyboard speed with my right thumb on the Samsung keyboard in portrait mode, I had extremely few errors. Apparently their algorithm also takes neighbouring characters into account in a sort of fuzzy logic, resulting in unexpected accuracy at high speeds as long as you don't try and correct yourself until the end of the sentence.
Strangely, I couldn't match the speed in landscape mode with two thumbs because the screen and keyboard are not centered on the device and one of the thumbs ends up doing most of the typing anyway. Error level was about the same as in portrait.
That said, I've decided to go with the Samsung keyboard for everything and throw caution to the wind.