I am looking for recommendations on an adhesive/ bonding compound for permanently adhering fibreglass to a factory bumper (SMC).

I have found 3M 08219 which looks to fit the bill well, I don't have the special caulking gun required however which makes it an expensive option
https://nationalautobodywholesalers....pair-adhesive/

Does anyone have any experience in other options from Evercoat? 887 or 898 perhaps?

Any other recommendations?