I may disagree with bottom-up as the focuses tend to shift toward teams mostly and keep the upper level process older and becomes somewhat a clash when meet in middle as companies would call it a compromise but non incremental approach. Volunteerism is good approach as it'd be an unlike a push and grasp the learning better as well as accepting. In order for the process to fully get into its sole adaption is by all levels collaboratively work in that environment, volunteering would be excellent but as more occasions that may not be the case. I wouldn't call it a big bang but a small product can be a good start. Teams from bottom may be considered a bit organizational siloed. Hope this helps.
I may disagree with bottom-up as the focuses tend to shift toward teams mostly and keep the upper level process older and becomes somewhat a clash when meet in middle as companies would call it a compromise but non incremental approach. Volunteerism is good approach as it'd be an unlike a push and grasp the learning better as well as accepting. In order for the process to fully get into its sole adaption is by all levels collaboratively work in that environment, volunteering would be excellent but as more occasions that may not be the case. I wouldn't call it a big bang but a small product can be a good start. Teams from bottom may be considered a bit organizational siloed. Hope this helps.
-Cyrus