You can't come close to doing the 'biggest size'. You need to be realistic about the brightness of the projector and what it actually is capable of delivering.
As well, when you go to a large screen size, you must have a VERY GOOD room for using it in. This means, dark/black walls, ceiling, and carpet in the room with absolutely no ambient light at all.
I would expect you could get a 200" diagonal image that is quite usable from this model. As you started going beyond that size, the image would just be too dim to enjoy.
Read the review, which says that with the proper screen in a dark room you could go as large as 260" diagonal with an acceptable image...https://www.projectorcentral.com/Epson-Home-Cinema-1060-review.htm
Be aware of the throw distance though! You need to have the projector back far enough to get a proper image size. Learn to use the calculator. For a 200" diagonal, the lens to screen distance (throw distance) puts the lens between 14'10" to 17'11".https://www.projectorcentral.com/Epson-Home_Cinema_1060-projection-calculator-pro.htm?id_=200
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