You can cut the access hatch approx. 245mm from the leading edge, also the 40mm x 20mm is an approximate dimension.
It is not really too crucial to be exact here with dimensions since this is an access hatch only and will be used as an exit hatch for the leads as well.

I left the strut cutout straight on purpose, i have been testing which struts to use. They all fit and might require a slightly different cutout that's the reason I did not cut it. As it turns out the Behotec will be too heavy duty for this plane, the plane is lite and the struts will require too much weight to compress or a very heavy landing.

Electron struts as well as JetsMunt struts will work better, and they will be cheaper for the end user.

As a result, I have ordered the JetsMunt struts and as soon as they are here I will post some pictures.The Electron retract units fit perfectly and the mount is pre-drilled for them. Blind nuts and screws are supplied with the kit as well to bolt the Electrons down.

Also note that the stabs are thin and it might be a small challenge to fit the standard size servos in there, but it is possible.
I opted to use MKS 6125, these are high quality high torque servos delivering 8Kgs cm at 6V, or 111 oz in. Savox SA-1256TG or SA-1258TG will fit there as well.