Me: very athletic 5 foot 5, 150 lbs man with a few months of Judo under his belt.
Opponent: 5 foot 11, 300 lbs national judo champ with decades of experience.
This motherfucker is impossible to move. I feel like the only way I could take him down is with illegal moves : double/singles and kata guruma.
I guess you can call this a twist on the 150 lbs karate female versus 220 lbs 6’3 gym rat.
If this is happening under judo competition rules, since you mention banned moves, than there is unlikely to be any winning tactics.
Someone with serious size AND technique AND experience advantage just has too many ANDS.
Look at it this way, if you could get it done what would that say about what it takes to be a national champ?
Judo competition is well out of my lane, but I am thinking two things. Either figure out the best position to try your best move from and go after it like no other, or just try to stall his attempts.
In judo I sort of translate that to grip fight like there is no tomorrow. Even if you have to spend minutes just playing paddy cake that is better than taking the big ride. Decide right now that he will work for it.
Tactics: Learn. You have nothing to lose and no ego. He SHOULD toss you. So anything positive is awesome. Resolve to make him work for it, than ask him for advice after. I have personally learned a lot from being an ernest and cheerful tackle dummy for better martial artists. Than when you face someone else closer to your size and experience you have your way with them.
Really though this needs to be a jellyroll and kmcnyc question.