I have a ProSport with 300xs and 1.62 gear case. I ran a lot with the trolling motor off when I had the 225Xs on the boat. I changed nothing with weight distribution. i will say that my tackle and fishing gear was always in the boat with the 225 (50lbs). On the top end, I would pick up 1mph if all I did was pull the trolling motor. Interesting to note, it was equally as effective if I pulled the trolling motor and set it in the back of the boat. I have a Minnkota Terrova 80lb 45".
I have done some radar run events with the 300xs. The boat was cleaned out of all my gear for those. As long as the trolling batteries were still in the boat I didn't have to add weight to the boat. Given early testing with moving the trolling batteries to the center and having extremely bad handling, I have never pulled the batteries to run or hit top end. I almost feel if I pull them I'm going to have to add a ton of weight so why bother. In one of my tunnels, I could pick up 3mph if I pulled the trolling batteries, so I feel I'm leaving something on the table by running with them, just not gutsy enough to run without them.
I have a level in my boat that I put in above the steering wheel. I run a touch heavier on the left side but not much. When I first started out I ran it much heavier on the left. My biggest issue was coming from a tunnels and the lack of respect for general weight distribution. In addition, not being particular about knowing where my neutral trim was and how engine height effects drivability. From what I have seen, most run XB-21's run near neutral trim. I get my best numbers .2 to .4 over neutral. (I don't think I have ever seen a rooster tail on my boat). After I'm on plane I set my trim to neutral (4.7) and don't touch it again unless I'm going above 90.
My biggest handling killer was engine height. Running under the pad makes my boat handle so much worse. I had to be all over the wheel to keep it on the pad at 65. With the motor .25" above I have no issues.