Like this one ???
Anyway good on you for having a go I hope you bring some awesome products to the table.... in many years from now there will be a few key suppliers in the electric skateboard parts industry... you may well be one of them.
Let me explain in more detail my design, The new Enertion motor mount is Height adjustable by a few degrees (the carbon fiber motor plate can pivot, up & down, on the three stainless steel pins)& it does have M4 set screws perpendicular to the truck hanger like you are suggesting..... I think its worth pointing out that the mount will not shift along the hanger if you have the correct clamping geometry, So I mostly introduced the new feature of, sets screws perpendicular to hanger, to prevent rotation on non caliber/enertion trucks, such as Paris that has a nearly round shaped hanger, there is no geometry to prevent rotation, so the set screws can clamp down and prevent it. This makes the enertion product a bit more "hackable" so people can experiment with mounting it to different trucks. For example I mounted it to a sort-of-octagonal-round-oblong shaped fibreglass handle on a hammer in the shed. The clamp forces held it very well, but with the set screws it could not rotate around the axis of the handle.
Although my new mount design is not reversible. I did seriously consider it, I think there is some benefits to having rear mounted motors, however IMHO there are not enough benefits to warrant this configuration, the main reason I did not go through with this is because of the truck geometry.
See in this picture, side profile at bottom right, the axle is not in the center, it is much closer to the right side.
To offer a motor mount that is reversible the centre distance must be increased substantially
to give the motors clearance of the pivot-cup assembly. Increasing the centre distance increases the belt size and also amplifies the forces on the clamp & hanger. Its like increasing the length of a lever, it gives you more leverage & amplifies small flexing/vibrating that might occur at the end of the cantilever. Also if you do actually want the motor mount installed on the "inside" then you will encounter more issues with deck clearance & will need to angle the motor upwards (assuming the motor mount is angled downwards) away from the deck, which puts the motor closer to the ground making it more likely to to be damaged by debris on the ground.
Please don't be discouraged by my comments, it is just my opinion, my intentions are to simply share my knowledge & experience of designing motor mounts. Trial & error can be very expensive! and delay your project substantially.