How I do my lower units is run a ratchet strap under the lower unit fin and hook it to the lower cowling so when it’s going back on solo I can ratchet it up and align the fly wheel at the same time so the splines line up. Idk if that makes sense?
Attach to a secure part and don’t put a ton of pressure on it
remove bolts and hand lower it down and lean against the wall. Replace water pump and seals. Pick it back up and slide it back into housing and bolt. Always have binacle and lower unit in reverse removing and re installing. DO NOT CHANGE SETTINGS WHILE REMOVED !! Its that simple.