Make a female mould too, using a thick(ish) sheet of balsa. Fasten the clear sheet firmly to this female mould, and hold about six inches above your cooker hob, keeping the sheet moving in a circular motion. As soon as the clear sheet just starts to go 'floppy', push the male (canopy shape) mould through the clear sheet and profile 'hole', all the way. Allow to cool, and then trim with a new scalpel blade, with the male mould still inside the moulded form.
When you make the balsa male mould, seal the grain with a coat of talcum powder mixed with clear enamel gloss varnish. When fully hardened, sand lightly, clean off the dust, and seal again with another coat of clear varnish, and polish when fully hardened.
ANY imperfections in the male mould will be reproduced in the moulded part, but this can be advantageous, as tape can be used, sealed under the aforementioned coatings, to reproduce frames etc.
Be prepared to have more than one attempt, as the 'knack' is to do the actual moulding in one swift movement, before the heated plastic cools.