I never thought about mounting spiders... Nice Ornithoptera. Not that I'm (anywhere near) an expert, but it would have been better if the left hindwing of the male was further upwards - symmetry with the right wing. Maybe I'm a perfectionist.
Yes, you don't have to inject hot water till the specimen is softened. This will not work. Just a little water, so that you can open the wings a little bit. Then put it in the relaxer for two hours or so.
I let them two hours in the box, even birdwings. Most times this is enough. During the winter I do the box on a radiator which is only a little warm, otherwise it does not work within two hours. But don't do this with males of Ornithoptera victoriae, they get brown stains into the green patches very fast. The head and the antennae are relaxed within two hours also by me, but I also dip them into hot water to be sure.