The EB will fit any gasser fuse made as it has a pretty close foot print to the vario gasser and it could be made to fit your two birds that you show I am pretty sure ... you would probably need to do some plywood work ..but that is what scale is all about ,,, doing your own designing .
Now would these light made fuselage made for electrics hold up to gasser vibes ... that I don't know . Most of these fuselages are made on the light side ... Just my 2 cents
Which leads me to another proposal ,, why don't you convert your gasser to electric and then all would be fine for these two fuselages ...
By just changing your bottom frames and buying the electric drive gears/ shafts /motor and esc ,, you could have an 800 size electric from your present eb gasser .
Larry C ----------Bergen R/C helicopters