Sigma DC Lens (for Crop) on Full Frame with Kenko 1.4x

I know this was discussed in length when it came to the Sigma 10-20mm, but has anyone tried the Sigma 30mm f1.4 (non-art) and the Sigma 17-50mm f2.8 on a full frame with a 1.4x teleconverter? I'm going to sell my 7D and most likely the 30mm and 17-50mm, but will probably keep the Sigma 10-20mm in the meantime and get the kenko 1.4 teleconverter. I'm just curious of the findings.

Here is a thread for reference:

https://photography-on-the.net …light=sigma+10-20+5d+1.4x

Thanks