Good morning everyone, I'm installing a vinyl fence gate today for the first time ever and wanted to ask for some pointers. Here's the photo of the posts that were already installed and redoing them is not an option. (https://imgur.com/a/AbiDL)

I got this kit from Lowe's (https://imgur.com/a/V77pY) and it says to subtract 7" from the width between the posts to get the right gate size and then it says to cut the panel rails symmetrically when possible (https://imgur.com/a/UWuaY) which in my case is not an option due to the preinstalled upright posts. According to their calculations the width should be 44" which falls approximately in the middle of the rail (https://imgur.com/a/zUrEW).

My question is the following: how do I go about making this as aesthetically pleasing is possible? Should I split the difference? Going up or down to the next rail is not an option as that doesn't allow for proper clearance for the attaching hardware. A follow up question is what is the best way to cut this vinyl? I have a circular saw, a jig saw and a Dremel at my disposal. I was told that the vinyl can crack and chip very easily. The gate that came with the kit is 65 ½" wide so I do have some margin to experiment with cutting it. I'm going to head out to the store to grab some supplies for another yard project. Thanks for any help and advice in advance.

P.S. This project is for the house of the woman that I'm in love with who's coming home today from a trip and things are "complicated" right now so please keep that in mind when accounting for the aesthetic part of this project. Thanks again.

Posting from mobile so apologies for any formatting mishaps.