If you had no oil leak before it's most likely just from the rocker cover seal. Did you fit a new one?
It will probably take a few minutes for the oil to travel to the bottom of the engine if coming from the seal. There's also an 'o' ring that fits where the distributor went on the earlier engines if I remember correctly from when I did mine... or it could be from camshaft seal?
No, can't give up now - just for an oil leak.... it's all down to commitment now!
It def sounds like something you've misassembled or disturbed (...we've all done it! )
you can sort it!
This is the same Balboa who wants to modify their Panda to be a fast road monster? I dread to think what we're gonna get when you try an engine conversion!