Well here it is: Unbuffed regina solo (only ate a cookie =3) 6min 9sec
With 50% damage potion and a cookie too 4min 13sec
I think with my current stats, it'd be pretty hard for me to reach below 6min for a unbuffed solo or below 4min with a damage pot. As you can see the clear time matches what i stated earlier around 1.5 times longer clear time for a unbuffed run. 369 (unbuffed clear time) / 1.5 = 246 (253 seconds was the actual clear time of my buffed run)
You can also take the 6min to be a upper limit and see that with 500 att limit remove the KR evie (who almost have identical gear/stats as me) reached 5min 30sec clear time. So for every 500 attack limit remove you gain about 30 seconds and with 2000 you'd arrive at around 4min clear time with 2000 attack limit, this is very close to what I predicted in previous post where the KR evie had a 148 seconds clear time with 2500 attack limit remove and a 50% damage pot. The 148 seconds clear time with a damage potion would translate into 222 seconds clear time without potion (3min 42 seconds).