Wide Exhaust Seat

I keep the exhaust valve seat "on the wide side."  I've read where a wide seat on the exhaust helps dissipate heat when the valve is shut . . . cooling the valve.  I could easily cut a 60 and a 30 and narrow the seat, but I'll leave it wide.  The 60 takes away material (which a guy might need for future valve jobs on this old iron) !