Curious about the conjecture.
Let’s consider the same scenario mentioned, C_2 has score 3 and C_3 has score 5 and I hold 4 votes and want to manipulate the fork. Under regular GHOST, there is no way for me to construct a block to be chosen as the head, as C_3 will always win (I would need to also manipulate the 3 votes from C_2 and construct D as is mentioned). In modified GHOST it seems I can take the head of the chain with only my 4 votes by constructing C_1 without the need of manipulating C_3.
Does this not decrease the number of validators required to manipulate the fork-choice compared to regular GHOST?