I tried a UH480 a while ago, and it was large enough for my short throw ratio. Now looking to maybe buy an old Prismasomic. Dimensions on the Prismasonic are 10cm x 12 cm on the lens side and 17cm x 12 cm on the screen side. Only info I can find on the UH480 is that it's 5" x5" x 7". Anyone know how big the prism is on the lens side?