First of all - get a centre stand
Practise the wheelchange in your garage where you can leave the bike till the following day when you don't get finished
I did the exercise on the back wheel without the centrestand and it took me more than two hours, taking it off, breaking the bead, taking out the tube and put everything back
Beleive me, if you don't do this on a regular basis you will struggle
I'm glad I did not get a puncture on the last trip, it would be the end of it
You must try to do the exercise with only the tools and mini compressor you take along on a trip, otherwise it's sensless if you've got a big tank compressor, etc etc
Would love to hear your story when you try this