Choose one from Automation-compatible types.
SYSUINT
(ie. VT_UINT
, unsigned int
) seem to be your best bet for both if the target platform includes both 32-bit and 64-bit architectures. For 32-bit-only, you can choose LongWord
(VT_UI4
).
If you don't need an automation-compatible COM library you can also choose Pointer
for THandle
.