I've copied here my post from the Tomic-Brands thread:
It's tough to say, I think in the 70s many times on grass tie-break sets were concluded around 30 minutes.
Could be the case. However, is there a faster tie break set recorded in the last 20-30 years?
I checked some tie break sets between big servers of the 90s and last century. Seems like few sets where under 40 minutes...