And there you were saying it.
I checked Pete Rose, Ty Cobb, Babe Ruth, Tony Gwynn all about .060-.070 difference putting Edgar in that group. Honus Wagner .678 VSLH, .707 VSRH, that's only .029 difference, almost entirely OBP although we only know the starters hand in that era. Nap Lajoiey was .058 difference with the same relievers unknown issue and Tris Speaker .060. Rogers Hornsby .010 with the same caveat or .089 in the 1000 or so PA we have complete data on. Lou Gehrig has similarly low split with partial data. Rod Carew .072 difference. Wade Boggs .761 VSLH, .898 VSRH, I didn't expect that.
I couldn't find one with similar slugging vs both handed pitching and there were dozens of others I checked that were further than. 070, many still .700-.800+ from the "weak"side.