You can support adiirc 64bit easily enough in your code by instructing users to download tsc64.dll and having them comreg it via /comreg "path\to\tsc64.dll"
Update: The installation has changed, Download the tsc64_1101.cab asset, extract, and run setup.exe
Once done, you only need to add one line to your $jsCreate() alias:
aliasjsCreate {
; ...if (!$~com(%name)) {
.!comopen%name MSScriptControl.ScriptControl
; This line will attempt to create a scriptcontrol using tsc64.dllif ($~comerr) .!comopen%name Tablacus.ScriptControl
if (!$~comerr) !return$~com(%name,language,4,bstr,jscript)
}
; ...
}