Trying to convert a Lo Pro to a Hi Wheeler is an exercise in futility. Do not even attempt it. All you will do is destroy two tractors and end up with garbage that has little to no value.
It is more than just the back wheels. The axle shafts, drive motor, front axle, front spindles, tie rod, drag link, fenders, implement lift etc are all different. Even the basic frames are different due to the ground clearance.
Essentially the 38, 44 and 48 decks are interchangeable between the two Series providing you have the correct lift links that connect the rear of the deck to the implement lift. However, the 38" deck is not wide enough for the Hi Wheel models and the 48" deck is a bad choice on the ten HP 200's due to lack of HP to spin it while cutting thick or wet grass.
Just keep searching for a 444. Eventually you will spot one that was listed minutes earlier and you can jump on it before anyone else does.