Time adjustment for Stock to 1+1

I'm using Xtol to develop 4X5 Delta 100 in rotary Jobo and can't find any *suggested starting point* for Xtol diluted 1+1. Lots of opinions for Stock starting points. Maybe there is a general idea of what amount of time to add when diluting a stock developer?

Thanks,

Start with the Kodak Xtol time for 1+1 in rotary for Delta 100 35mm, then adjust from there?
http://www.kodak.com/global/en/professional/support/techPubs/j109/j109.pdf

Otherwise if you have times for 4x5 Delta 100 in rotary vs small tank, look at the % difference?

Ilford sheets also state start with up to 15% less time than small tank agitation for rotary.

Looks like it'd be 7 to 9 minutes to me at 20 celsius.

The ilford development chart doesn't specify differences for 35mm to sheet as far as I can tell.

10.5 min for maybe inversion tanks, so you may reduce for rotary about 15%, sorry i am not expert and i can't help but i post something to be active than nothing, you can give it a try and see how you will end with, if you are looking for a certain look and accurate then better find another answers, here just for starting point testing.

http://www.digitaltruth.com/devchart.php?Film=Delta+100&Developer=Xtol&mdc=Search

I do Delta100 135 and 120 in a rotary tank with Xtol stock, 7mins at 25° celsius. That gives good contrast which print well. I expose as IE 100.
It took me a bit of experimenting to arrive at this - you'll probably also need to do some testing
Peter