For what its worth if it were me - while the engine is out and your having the crank reground.
I would whip the head off and inspect the bores and pistons. You could replace the rings quite easily at this stage, but it maybe worth having the bores rehoned and fitting new rings, you would need to make an assessment based on the bore conditions.
While the heads off inspect the valves again now would be the time to replace the guides / seals if necessary and reseat the valves. This isn't a hugely costly job if you strip the cams and springs out yourself.
Get the head checked for flatness and have it skimmed if necessary.
Then check everything is spotlessly clean, oil ways, waterways, surfaces etc...
Of course if you wanted to push the boat out you could look at having the bottom end balanced.....
Reassemble carefully using new bearing shells on the crank - make sure they give you the correct ones when they grind it. Use new gaskets throughout. Fit new tensioners, belts plus and filters, new oil seals everywhere! Just buy a full gasket set!
Check your sump plug while the engine is out... these seem to be a weak spot so best fix it now.
Make sure you run it in do 1000 miles generally then change oil & filter and torque head down again! Make sure there are no leaks anywhere!
This doesnt have to cost that much if you can strip the engine down to its component parts yourself and are confident enough to fit it together again correctly - but while the engine is out it seems silly not consider all the key areas!
The amount of oil you used seems way to high it must be going somewhere did you notice any clouds of smoke behind you? Is there oil along the underside of the car? Its either a piston ring / bore issue, valve guide / seal issue, oil seal leaking somewhere, or leaky sump...