Focusing on the aircraft in the picture, lifting tail aircraft are essentially bi-planes. The single lifting wing has proved to be more efficient long ago. Simple adjustment of the CG removes the need for a lifting tail. This plane could be flown that way.
It is the job of the tail to set the wing at a given AOA, using aerodynamic force in flight to hold that AOA. The thought of tail "downforce" creating a huge lift penalty is not true. In flight, it is the angled, lift producing wing that creates the "induced drag", while the tail rides along at its lowest drag. Torque around the Center of Gravity keeps it that way, unless some disturbance changes the wing AOA. Many aircraft, like the Piper Cub, use a low aspect flat plate as a horizontal stabilizer, with an elevator to create a crude, but adequate "tail wing" to change pitch or trim as needed.
Only when CG is placed behind the center of lift does a lifting tail become necessary, but directional stability is affected because now more wing and fuselage area is ahead of the CG.
Many planes on the ground show the "decalage" of the tail appearing to provide a lot of downforce, but in the air it will "weathervane" into the wind, torquing the wing to the desired AOA.
Moving the weight forward on that model needs only adjusting the fore and aft engine thrust percentages for VTOL. In the air, treat it like an airplane, with one lifting wing and CG slightly forward. And yes, keep the T-tail.
An add on for those who wish to further understand lifting tails. The whole point of a tail is to increase directional stability. Taking a wing without a tail, and balancing the center of lift with the CG still will have some directional stability because the center of lift is usually at least 2/3s of the way forward and the back portion of the wing acts as a "stabilizer". Add a tail to this and you are far more directionally stable, and there for able to move CG behind wing center of lift and still have directional stability. This is by no means fatal in all cases, but will make the plane less stable and easier to turn. Good for fighters, not for cruisers.
For the modeler building the VTOL above, no need to get stupid when simpler solutions are at hand. Make it an airplane first, and use differential thrust for VTOL. At least 2 of the motors could be idled in cruising flight.
Regarding the Proteus, Rutan wanted a high flying heavy lifter. A very high aspect wing is most efficient, but presents structural challenges. So he made a bi-plane. Colonel Pezzi flew one to 51,000 feet in 1937. With Rutan, one strives to understand function as well as form.
PS. A lifting tail is entirely safe as long as the CG is within design limits. The XB-70 certainly is a "lifting tail". People get into trouble moving CG behind design limits because they use up elevator throw to create lift and also make the plane less stable than it is designed to be.
But take a model of an XB-70 to the hill and fly it off with an average sailplane model of equal weight and wing area. No contest for gliding efficiency, but the XB will have a much wider speed envelope under power.