So I love the Hobby King electric retracts but their plates can leave something to be desired. This plate is designed for their metal trunion model with a 44mmx41mm mounting plate.
https://hobbyking.com/en_us/servoless-retract-with-metal-trunion-44mm-x-41mm-mount-2pcs.html

I've installed this on my own aircraft to test it and it seems to be holding fairly well. I've got it on my Top Flite AT-6 Texan which weighs in at about 7 pounds. I printed in ABS and the strength seems good but I do not recommend you fly when it is colder out. It makes the plastic more brittle and I have had a failure. It was 23F outside.

I've beveled the holes to accept the stock screws as well. I added a bit more thickness for added strength but the stock screws will seat just fine.

Anet A8

No

No

0.1

100

For sure you want 100% infill to beef this up but added strength comes from 0.1mm layer height and proper extrusion for the best layer adhesion. Use at your own risk if your machine is not completely dialed in.

PLA is more brittle than ABS so I would highly recommend you only print this in ABS. I've not tried nylon but I suspect it would be better than ABS.