Jim, Your parameters drop in high volume just fine. Typiically though I see the figures reversed. .030" dia Internals and .025" dia Externals. What we like to use is DHS (Drilled Hole Size) + .012" +2AR (2X the Annular Ring). That's for Externals (outerlayers). For innerlayers we use .014" for the second number. This way the manufacturing tolerance is a locked in value and the annular ring (requirements) are a variable. Groovy