I dont have any experience with InnoSetup.
The most important thing is the [Run] register/unregister section. (and you dont need the regasm/codebase argument in NetOffice)
You use an hardcoded path to regasm.exe and this may cause issues. In .MSI deployment projects you can use an option "Register:vsdprCOMRelativePath" and the windows installer service want register the addin for you - no need to call RegAsm directly. I suggest you to find out may InnoSetup has a similar feature here. (i'm 99% sure there have for umanaged dll's but not sure for managed/.net dll's)
The most important thing is the [Run] register/unregister section. (and you dont need the regasm/codebase argument in NetOffice)
You use an hardcoded path to regasm.exe and this may cause issues. In .MSI deployment projects you can use an option "Register:vsdprCOMRelativePath" and the windows installer service want register the addin for you - no need to call RegAsm directly. I suggest you to find out may InnoSetup has a similar feature here. (i'm 99% sure there have for umanaged dll's but not sure for managed/.net dll's)