I'm having a hard time to do these tasks because it's too repetitive ... So after 4-5 hours, I've decided to make the access hole for the bell crank in the tail area. In fact I've made an access hole on both side based on RV friends comments. I've used my home made variation of the joggle tool to joggle the skin. The result is OK but not great. But once the cover is over it does the job as expected !
The little darker spot on the first picture around the holes is simply a little piece of dirt ... the hole has a perfect shape !