The Phantom and Weight Lenses cannot be combined due to sharing the PROP_TOUCH attribute. I was not able to find anything about this anywhere, except the entry in the Lexica ("some combinations will not work"), but I feel this reddit comment (from a year ago :V) should override that.

The point of the Weight lens being terminated is to use more mana (as silk SHOULD be more expensive). This is a non-issue.

Was just wondering, but Vazkii had said she'd let them combine, so I'll wait for what she says.

Looking back at this, you are correct. Closing.