I have Landpride QH15 and 1272 Landpride mower. I do not have an extension, but I bought mine all together, so my PTO shaft was the correct size from the get go.
On the QH15 it adds ~4" to the needed length of the PTO shaft.
Mount the mower, Pull the PTO shaft apart so one half is still on the mower and the other side you can connect it the tractor... then line both up side by side to the mower shaft. If you have 8" or more of overlap... you are good. I would not go smaller than 4" of over lap (I think 6" is recommended).
Mount the mower, Pull the PTO shaft apart so one half is still on the mower and the other side you can connect it the tractor... then line both up side by side to the mower shaft. If you have 8" or more of overlap... you are good. I would not go smaller than 4" of over lap (I think 6" is recommended).