personally , i was planning to use windshield glue (on the bonnet i’m making)
thanks evodelta,As aga says im also planning on using an adhesive that is designed for holding glass to fibreglass.I work for Wrightbus and we use sika 255fc a lot for this type of thing.the spec sheet says it is also suitable for bonding fibreglass to itself.seriously strong stuff and goes off in about an hour.We havnt had any problems with anything warping so far in work so hopefully it will be ok.