Tar.xz based 11.10 Wubi is incompatible

I wanted to install 11.10 but also downloaded 11.04 Wubi the day before 11.10 Release as contingency. 11.10 Wubi failed three times in a row due to tar.xz based nature which is appropriate for Non-Windows OS vs Windows 7. 11.04 Wubi succeeded due to
torrent based nature which is appropriate for Windows vs Non-Windows. However, when I tried to upgrade to 11.10 via Update Manager, I had total failure the 1st time and after 11.04 Wubi Reinstall, a partial failure the 2nd time due to minor problems with LibreOffice indexes & Firefox flash plugin plus the inevitably slow or erratic boot due to the lack of normal post-upgrade cleanup of conflicting remnants.

Upgrade via Update is prone to failure because it takes forever to download the 1361 to 1466 updates and often there's a missing or corrupt file which causes Update Manager to abort & abandon the mess without any cleanup. Please excuse me if I don't rush into a 3rd five hour experience, especially if the 2nd attempt has any functional success.

Someone suggested I download the 11.10 iso cd image to the same location as the tar.xz based 11.10 Wubi which might then utilize the the iso instead of the tar.xz files. While this looks good on paper, I have to ask if anyone has ever had any success with this method.

Windows 7 is my primary OS until I'm more comfortable using Ubuntu and will remain necessary afterward. In all cases, I have no use for playing games with my Windows Partition - so it's Wubi or Bust. My hope is for Ubuntu.com to offer torrent based
11.10 Wubi soon ... or then 12.04 or then...