Two problems, first as its all been said 1/4" is not a lot for a countersink bolts, second with a countersink bolt you use Allen type wrench to tighten them, you won't get them hold as tight as a normal fixed head bolt would.
There bolts, buy good quality bolts like caterpillar use's and they will last a long time.or just replace them every few years once they get gouged up. I have the same bolts on my cross member for 10 years now, yes they are so worn down the zinc is gone and gouged to the point a socket fits hard.
But I bought Cat bolts and they have a larger head and made to a higher quality standard.
1993 YJ 4.0 60 Front, Rear steer 60, bolth spooled, 5.38's, 700r/241 39.5 iroks and beating it like it owes me money.
And on the 8th day, God created the 14 bolt....