Welcome to the forum!
I've been sailing happily with different electric motors and the kind of triangle rig you mention.
![2758](./gallery/image.php?mode=thumbnail&image_id=2758)
There's a small difference in my setup in that the triangle is separate from the mainsheet and has a block through which the mainsheet runs. I tie the bottom middle of the triangle to a hook underneath the transom coaming (click on the image to enlarge). That centers the block on the triangle and unlike a triangle formed by the mainsheet, it's height is also fixed.
![2942](./gallery/image.php?mode=thumbnail&image_id=2942)
The effect is a
slightly different angle of pull when the boom is sheeted in, which helps in sail trim and that's why I did the upgrade, but it does not prevent the mainsheet from risk of getting entangled, whether with the motor, the stern cleats or a corner of the stern. What does make a difference is to pull in the main while gybing. That tends to prevent any issues, because there's not as much loose mainsheet hanging at the back.
As I approach a gybe, I pull the mainsheet taught which helps bring the boom to center position. At that point, I do the gybe and as the boom comes around, I let out the mainsheet in a controlled movement. Not only is that the proper technique,
as I understand it, but it does prevent the main from getting entangled.
For the most part, that solves the issue for me. I often grab the mainsheet below the boom for that instead of pulling it through the mainsheet swivel.
Tacking upwind, there's usually so little slack in the main that no special attention is needed.
The top picture actually shows the motor placed rather awkwardly. It would need to be rotated 90 degrees CCW to be deployed anyway, and that would move the operating lever out of the way. But as you can see, my setup is relatively tolerant.
![2651](./gallery/image.php?mode=thumbnail&image_id=2651)
Aft boom sheeting has its advantages. The sheeting angles are just a bit better than with center boom sheeting (and even better if you upgrade to a fixed triangle). Another advantage, in my view, is that it is really easy to fit a ratchet block.
![1852](./gallery/image.php?mode=thumbnail&image_id=1852)
I like that particular model of ratchet block in its "auto" setting. It runs free, if lightly loaded, but will resist the pull of the main when under tension (from wind and you pulling at the free end). It allows me to hold the main in my hand in most conditions, particularly going upwind in gusts, and I now rarely use the cleat. It's easier to release the main to respond to a
gust and less chance that a gust will cause a capsize.
To complete the rigging, I installed a 12:1 boom
vang. This is strong enough to use upwind and prevents the boom from rising as you ease the mainsheet. That prevents your sail from changing shape and becoming full, which would power it up. That would be the opposite of what you need in a gust and therefore you'll find that you get more control in stronger winds with a vang. Made a noticeable difference for me.
![2663](./gallery/image.php?mode=thumbnail&image_id=2663)
For racing it means I can hold my own in stronger winds, and for cruising it's an extra safety factor if the wind picks up and lets me postpone reefing if the gusts are only occasional.
That said, the choice of rigging tends to be highly personal. The DaySailer is a bit unusual in that even if you plan on racing it, the class rules are not restricting you from doing it your way. That has led to all sorts of interesting setups. I started out where you are and did a few upgrades along the way. I'm now pretty happy with my setup.