Hopper Replacement Window

[muellerm123]

Hello. I purchased an American Craftsman by Plygem hopper replacement window to install in my bathroom. I am going to be re-framing the window to the smaller size of the hopper window I bought. The hopper window does NOT have weep holes.

Is a sloped sill necessary for the hopper window?
If so, what do I do about the gap that will be formed beneath the square window bottom edge and the slope?
Can I just install the window on a flat sill and then add a slope afterwards in the exterior sill space and seal it all in?

The installation instructions don't even mention or outline a sloped sill (like they do on other window installment instructions).

Thanks in advance!!

[Windows on Washington]

If its capped and the water management is correct, not needed. What are you doing for trim on the outside? Capping, PVC? But if you are just trimming it out with wood, I'd have some slope on the wood subsill.