DD-X at 1+6?

There are published times for DD-X at 1+6, and I'm looking for a starting point. 1+9 times on MDC are roughly 1.8 times the published 1+4 times. Looking for a rough multiplier to apply to dilutions in the middle. Thanks.

Extrapolating from that, I get a 1,25 multiplier.

Acros in DD-X 1+6 for 12 minutes looks pretty good (68F).