Shanghai HOHO Industry Co., Ltd.

What type of silicone can be used with HOHO Smart Film/smart glass?

Use only Neutral Silicone Sealant. Do not use Acetic Silicone.
Just because Silicone is neutral cure it does not mean it is proper for PDLC Glass. It depends on what Silicone neutral cure is made out of.  For us, We only recommend the silicon glue made in Japan,  Toshiba Brand,  Model: Toshiba 781/381 etc.