Zill,
It depends on what you expect to get from coaching.
5% of coaching is to identify flaws.
95% of coaching is drilling millions of reps to ingrain a new habit.
The first part will show diminishing returns rather quickly.
If you take 2 lessons, you will still have the same issues on the 3rd lesson (and for weeks after, frankly)
But, you will use the lesson to drill and correct your flaw.
You may not correctly ingrain new strokes without live feedback.
Uncoached players hit 5 days a week for 40 years stay at 3.0 and 3.5
They have perfected their broken strokes beyond the point of no return.
I doubt you are even a 4.0 so focus on the process.
I don't even know what 6.0 means, I like that you have delusional goals
If you like drilling and taking lessons, then go for it.
But, lessons are not the only thing you will need.
You'll need to play a variety of players in matches.
As an adult, to even get to 5.0, you may need to quit your job.
I have never met anyone who has reached 5.0 who started as an adult.
You are correct that you'll need to play 6-7 days a week.
You also need to play more than once a day. That is a given.
College players play 4 hours a day, 6-7 days a week.
Personally, I use a multi-tiered pyramid approach to coaching, to maximize value
Pay an expensive former ATP ranked coach, and have him identify flaws.
You supplement this with cheaper $50 coaches to feed the drills, several more times a week.
You can also hire 5.0 college kids as hitting partners.
I also do the drills for free with various hitting partners at the club.
You don't need a to hire a $150 guy to do the work of a $50 guy.
Then you need to play matches a few times a week, so see if the drills are translating into real life.
This is the only way to see if your new strokes are becoming permanent and automatic.
Once the skills are reliable in match play, you can move onto drilling the next skill.