Are there not default guidelines that you can work from as a starting point?
My L told me that me getting full physical custody would be a no brainer because I was the constant and ex-shat was working 80 hours/week.
We then agreed to make up our own visitation schedule between the two of us. But if one of us disagreed we would default to the parenting time guidelines. Honestly, making up the schedule between us turned out to be more of a burden on me because I was accommodating his working schedule and he seldom accommodated me. So within a year of D we had defaulted to the parenting time guidelines (EOW, four hr midweek visit, holiday schedule). He does not exercise his midweek visits.
So, if there is a default schedule, use that and make him prove that he will exercise his time.
If there is not a default schedule, then make an 80-20 in your favor (based on the fact that you are the consistent parent and his travel schedule currently prevents consistency) and make him show that he is going to change his schedule.