sorry to hear that you had to do house work /honey doo's.......... I'll see if the thread pitch and diameter is in the owner's manual ....As far as the UCD3d-40 The only problem Iv'e heard about is the stab's not holing up ,I don't have one so I can't speak first hand ,Just what Iv'e read in this forum....but you can put 91's in them..... maybe even a ys 110fz ....BWHAHAHAHA ...I my have to look into that....as far as the CG I have mine just behind the stock #'s in the manual...If you use the YS I would put the rudder servo in the rear like Father Joe has done .... this should keep you from adding Penalty weight to you'r plane......No lead in the ass....I'll go look in the manual for diam&thread....Well it isn't in the manual....Anyone else have the info LL is asking for....?????....JW