I would think that anything less than 50% custody would mean a serious legal fight, if I were you.
Their offer smacks of low-balling, hoping that you will come back with a counter-offer that is lower than 50% that they will jump at.
What exactly is your lawyer doing for you FIB? I know you like her and all, but I can't help but feel that she has woefully underrepresented you through all of this. In this day and age there is absolutely no reason that I can think of why the father of two children would not be entitled to half custody.
I hate that this madness continues for you, re: dealing with a spouse who remains intent upon bringing you as much pain as possible. The woman really seems unredeemable to me at this point.
Stay strong and do everything in your power to gain a settlement that you will be able to accept for the long haul.
Blessings,
Bill
"Don't tell me the sky is the limit when there are footprints on the moon."