I should have mentioned that I use a Jobo Processor. As such, I am not sure about the 60sec agitation times.
In addition, I am shooting/processing 7x17" sheet film, so need a decent amount of developer to avoid premature exhaustion due to this film size. Thus, I go with 1:20.
Given the anecdotal time correction from continuous agitation to non-continuous is an additional 15%, 1:20 at 60sec would be around 8 minutes (based on the information you listed above). It might be worth having a look at The Massive Development Chart to see what differences there are for other (listed) films where both Ultrafin 1:20 and 1:30 times are given, and extrapolate the difference time ratios to this 8 minute starting point.
A bit of testing will be required, though, given the vague nature of the current information!