Using different 1B model as verifier makes sense, yes. Using Llama 8B finetune as verifier to compare 1B inference time scaled in comparison with 8B makes little sense to me.
Using 3B model with 8B verifier against 70B model would make sense too. This being said their performance barely crossed 70B line with 256 examples. This is 256*(8+3)/70 ~ 40 times more computationally expensive than running 70B model as is.
"1B solver + 8B verifier + search" beating 1B-0-shot or 1B-majority as baselines isn't illustrative imo. In other words, by using larger verifier, HF's replication fails to establish a "fair" baseline. Still an awesome blog and release/repository from HF's group - I love it!