....is it worth the hours put in?
I know it comes down to me...
You would get out of it what you put INTO it.
That is all that REALLY maters. If it is YOUR DREAM, and YOUR DESIRE, then it falls fully on your shoulders.
If you don't mind working just to pay the bills/payroll, and maybe cut yourself a check every now and again, or paying your utility worker more than yourself, and busting ass for the first year JUST to hopefully, if EVERYTHING goes right, make a profit, go for it.
If you are already in the mindset of "is it worth the hours put it", that kind of turns me off. You say you are willing to be all in, and all in means ALL HOURS(which you would be, you are never "off"), so asking if it's worth the hours to put in is a moot point.
There is a LOT of fun to be had, a lot of great experience to be gained, and if you are a Chef who likes to cook for your ego, than there are few things finer than your name above the door, and guests in the seats. There is a LOT of freedom when it is YOUR gig, and you can run what you want, when you want, and how you want. It can be one of the BEST FEELINGS IN THE WORLD to know "I did this". With a 30 seat place, to turn a profit though, I hope that you would be prepared to do breakfast(at least on the weekends, so Brunch too), lunch service, and of course, dinner service. . .now, if you have been in the bizz, and know what's up, that is a lot of work. If you are down for it, go for it. you are going to have to focus on volume, and turning tables!
If you are a 30 seat place, and plan on dinner only, you need to do some serious number crunching and see what your average ticket per head will have to spend in order to break even. . .whether it is a Prix Fixe Menu at X amount a head, or a la cart, then you need to look realistically if the area supports that type of dining, will it be a full house every night doing what you will be doing, or will it just become a "special occasion" type place.
If I were to ever do it again(partner/own/operate my own place), it would be a fun, laid back place with glorified regional bar type/comfort food, a wide selection of draft beers, excellent happy hour specials, and put ego on the back burner(or use the blackboard for specials), and just have a more realistic go of it. I wouldn't get back into a White Table cloth scenario again, or maybe I would, but someone else would be cutting the check. I have learned to LOVE having a steady salary, no late nights, and no weekends to go back to the line. But, that's just me.
You said IF a lot in your post, and that's ultimately it: You will never know IF you can make it, unless you do it. There is a big difference between knowing and thinking though. Just study the numbers, try to change that "IF the numbers line up" to, "I can project X amount of $$$, every month", but even then, it's the nature of the beast, no one is going to be forced to walk in your place, so it goes back to IF they patronize your business. . . SO many IF's lol, only one way to find out, and there is NOTHING any of us can do for you(besides write rambling, long, posts like this, lol).