1st tournament was probably your best chance at placing well, since he was around nicer fish at one point in day. Did you try drop shotting as well or maybe a shaky head when he caught those bigger fish? Or even try something bigger like a Jig to try and get those bigger fish to eat?
The second one could go 50/50. Since both your weights were similar either you weren't around bigger fish OR neither of you were using the right technique to get those big fish to bite.
Third one is tough to say. I know how hard it can be to fish slower presentations when someone is fishing fast with a crank. Unless you have a crank, spinnerbait, swimjig, chatter bait, or something that you can fish at a similar pace its almost impossible to fish it decent. What baits were you using when he was cranking, I'm guessing a slower moving bait since you said it was hard to fish it effectively.
List the baits you used for each specific tournament to give us an idea of what your using.
Personally if I'm looking for bigger fish I almost always pick up jigs, frog, buzzbaits, swimbaits, big worms, bigger sized cranks and the punching gear. A lot of this will depend on what your boater is doing but those are some ideas of what to have handy and utilize. Even when I'm not fishing a tournament I fish with the mentality of go big or go home. That doesn't always mean a big bait, but more times than not the lures i listed will get me a few 3-6lbs each time out.
I'm sure others will add more advice.