I think I have this figured out for the most part but looking for validation from expert strangers on the internet.
Renovated the kitchen in this 1960's house. I think it probably has been renovated before and there was a ton of power in the kitchen. 240V for the range, 240V for an electric griddle, and 6 more 120V circuits. In our renovation we went with a gas range, so only needed 120V for that and then got rid of the 240V griddle circuit.
The garage is on the other side of the wall (conveniently) so now I want to use those circuits for the garage. I'm leaving the range circuit as is but just flipping it around in the wall. Will be using this for maybe a welder later down the line or maybe way down the line an electric vehicle charger. Don't know yet.
But currently the garage only has one 120V outlet and I'd like some more for all my power tools. (it's a typical shop/garage).
I'd like to take the 240V circuit that was feeding the griddle and split it into two 120V 20A circuits.
Here's my plan I'd like multiple second opinions on:
Existing circuit starts at the panel with two 30A breakers with handle ties. It's 10/3 wire with ground (black, red, white, ground). Black from one breaker, red from the other, neutral to the neutral bar, ground to the ground bar. As expected.
So I'm going to replace those 30A breakers with 20A breakers (with handle ties) and then in my circuits in the garage I'll be sharing the neutral (with pig-tails, not the device pass through). I think I also might just make this stupid easy and do a 2-gang box in the garage so there's just one destination for the existing wire. Neutrals go together, one outlet gets black hot, one gets red.
Anything I'm missing? Code wise I'm compliant?
Here's a photo of the current circuit from the panel perspective. The circuit in question is the two 30A breakers on the right side coming from the white wrapped wire in the middle KO (the breakers that are currently off).
Edit: Mistakenly labeled the original wiring as 12/3 with ground. It's actually 10/3. So additional question is can I leave the breakers as is? Maybe install 30A receptacles, or even just 20A receptacles and have the extra overhead...?