Couple hundred gems invested
Score : 7300 (No Glossy/Prismatic)
Summon 3 dinos on the field and keep destroying bakura's monsters whether in atk or def position. making him take battle damage is fine as long as you don't bring him below 2000 LP. Let him have at least 2500 LP to be safe.
Set Exchange face down so you don't discard it, use it to get back Panda or a core card if he uses his exchange to do so.
Set Mirror wall ASAP so he won't be able to steal it using Exchange, he will prioritize mirror wall above all else.
Combo : 2 Cards left in your deck > Activate mirror wall and pay 2000 LP next turn.
1 Card left in your deck > Tribute summon panda
0 Card left in your deck > Summon piranha > Fuse summon Master of Oz via Polymerization/Fusion Gate, Preferrably polymerization to ensure gravelstorm won't ruin the combo.
Activate gift of the martyr on master of oz > target piranha > Destroy bakura's monster (if any) using dino > final hit with piranha directly.
Important : If bakura summons a monster in attack position you have to destroy it because on the next turn he would either tribute summon or set a 2nd monster face down and activate Ectoplasm. YOU CANNOT LET HIM ACTIVATE ECTOPLASM.
Note : I have not tried this but you can maybe replace Susa Soldier with Hieroglyph Lithograph. This may allow you to have exactly 1000 LP of lower before doing the final hit and could count as "Low LP" bonus. Would bring Score to at least 7800 with NO Glossy/Prismatic