So I did exactly what you are talking about at around level 48. I dumped everything into restoration tree. I was out of mana many many times in dungeons. I ran the 100% resto build up until about a week after I leveled to 60. It was at this point man potions were costing me too much time to farm herbs for. I had some decent gear by this time. Not anything pre raid best in slot, but some decent blue intellect and spirit cloth and leather gear. I did some googling on the internet and learned about the moon glow restoration build. I redid my talent points to something very close and have not been happier.
I use rank 3 and rank 4 healing touch most the time during dungeons. So if a group member is less than a 1000 deficit, I use rank 3. If a group member greater than 1000 deficit, I use rank 4.
I try not to use regrowth, but sometimes if I know there is a large amount of damage coming in on main tank, I will use a rank 5 Regrowth. Regrowth is a killer on mana.
I use the highest rank rejuvenation on main tank to Buy me time to heel damage classes.
In those moments when the chit is going to hit the fan, I use the highest rank Regrowth followed with natures swiftness and then the highest rank healing touch. Know this Though; this will require you to use your innervate on yourself and its fine if you are in a 5 man, but a NO NO in a raid.
As you get healing gear, the talent build performs better and better. The moon glow build is a mana efficiency build. It thrives on plus healing, so the main focus of your healing is going to come from healing touch, but do not worry about this so much at first. It wont be until you get healing gear that you will notice what I mean.
As for natures swiftness, Eventually you will find that you rarely use it. Once you stop using nature’s swiftness it is time to redo your talent points to include regrowth.
Swiftmend was a life saver for me at first. I found myself using it all the time when I had it. Once I went moonglow, I learned that if I could not save a group from a wipe, chances are we were going to wipe reguardless of my healing abillities.
So just one last thing I would like to mention. This is more for giving you an idea of which rank spells to use as obviously your gear is probably way different than my gear. I use details. I keep up two windows from details. Healing and overhealing. With these two windows you can better adjust which rank spells you can be using. you want some over healing, but just enough to give you an idea of where your healing is. I use the healing window to see where I am compared to other healers in raids and also use the overhealing window to judge if maybe I need to use a rank higher or maybe lower. Overhealing window is relative to wasted mana too. So the less overhealing you have, while having some, the more mana efficient you will become. Remember you do want some overhealing. As your gear gets better, obviously you will be able to use lower rank spells, thus using less mana.
GL and HF
Below is where you can see the build I’m talking about. Just copy and paste everything below into google search window and it should show the website.
warcrafttavern guides pve druid restoration guide for wow classic