Should i transplant from this 2oz mini solo cup to...

Go straight into the final pot. You really don't want to transplant autos though due to the stress it causes. Any stress that causes the plant to slow growth will directly lower your yields in the end. The plant will 100% need transplanting but it doesn't seem big enough yet. I usually transplant once the plant's leaves have gone over the edges of the solo cup. In the future if you are gonna grow autos just plant them directly into their final pot and water carefully until its bigger.