Today, let's try transposing this hymn setting a whole step up (from A major to B major). B major has 5 sharps (F#, C#, G#, D#, and A#).
Here is the score and a file for listening. Practice it and play correctly the transposed version 3 times in a row without mistakes.
Then post your time to comments. Let's see if you can complete this exercise in 5 minutes or less.
Notice, that the point of this exercise is of course to get you more fluent with the transposition. However, you can play a few times, make mistakes, correct them as you go. It's not a problem as long as you finally play it fluently 3 times in a row. Even the time spent is not a problem - there is no need to rush.
But ideally, the real skill is to transpose it sight - from the first try without mistakes. The tempo, of course, could be rather moderate or slow. This level of proficiency is extremely useful for church organists.
That's what the AGO sertificate examinations require and that's what we will try to achieve in my upcomming Transposition for Organists Level 1 course.