LR - "I guess the real question here is what do the mainline folks like to see, slightly lower TT and a good amount of PIC time or the opposite?"
That's the point of making realistic assumptions about your resume if you choose to stay with just the C-17's or do the regional and C-17 route. Generic words, IMO, are meaningless.
What's "a good amount of TPIC time" vs. "the opposite"? Is it 4,000 hrs, 2200 hrs 121, one or two civilian type ratings and 1800 hrs milita
ry with 500 hrs TPIC in three years(1,000 hrs/year, 700+ 121, 275 mil w/180 TPIC/year)?
What's the pure C-17 route? 1900 hrs TT with 600 hrs TPIC(300 hrs/year w/200 TPIC)? What can you generate if you bust your ass? How much if you say "ah, that's good enough?" What's your drive?
Assess your options and project that into two different resume/career tracks.
Project that out for the next five years. If you go to a regional in five years you might have upgraded. What's your plan of action if it takes five years? Eight years?
A family is great. Kids are great. It sucks having to bust your ass when it takes time away from your family. But every month sooner that you get hired is over $27,000 a month, in today's dollars, at the end of your career. Getting hired six months sooner is a free college education for one of your kids. Get hired a year earlier and it's two college educations. Seniority really matters. You'll see the difference every month you bid. That's why guys are scrambling to get hired.
The majority of airline guys will tell you that keeping the pedal to the metal is important until you get hired with a major. I don't think I've met the guy yet that said "I wish I was hired later".
Guy had a flow date about 18 months in the future. He was waiting for it to happen. I asked him why? Hadn't he'd busted his ass to improve his resume and abilities? With a guaranteed job he took his foot of the gas and was waiting for his class date(flow). Twenty plus years of drive disappeared because he had a flow date in 18 months? He took it to heart, started chasing the job and got hired 200-300 numbers sooner. Everyone wishes they were 200-300 numbers more senior.
There are no easy answers. The harder you work now the more likely you'll reach whatever gates the majors might have for you sooner.
Good luck.