Micro Kristal Klear, or normal PVA (which is basically what KK is) is ideal for canopies. Use it to glue the part in place, then a bead run into the joints will seal it, can be painted over, and make it look like part of the airframe, rather than an 'add on', if the aircraft type looks that way. Good thing is, if the part is positioned incorrectly, it can be easily removed and fitted again, even if the 'glue' is set, but when set, it is firm enough to hold.