The question was not so much about what is good practice, but rather what is necessary. If the head had to come off after 15 hours of use, it is likely going to have carbon buildup, and I could not see someone going to the extent to strip the head of valves/springs/guides and soak it for something that is perfectly acceptable to put back on. Now in my case, the carbon build up is excessive, and the plan is to remove as much as possible and depending on the results reassemble. If the head looks questionable, then it will be disassembled and cleaned simply as a matter of being able to inspect it.
DT400, thank you for your explanation of the issue with the deposits.
I am a firm believer that if there is nothing wrong with it, then don't try and fix it.... so if some level of deposits are ok, then that is what I am aiming for.