Valve guide trimming, how much

Been running old Isky 505A & 505T in my turbo /6 with guides cut down to .665 - .670 from spring base. Many options for seals, I run rubber "bonnets" with diameter reduced to clear triple spring ID. Couldn't make teflon seals fit w/o removing too much guide. I replace seals frquently while "refreshing build". good luck.