New rope and new blocks

Today my new rope arrived, and yesterday my new blocks. Everything is being replaced. For the gun tackles I have chosen 2.3 mm blocks with 0.3 mm rope. In the photo the rope lies with a block on a carriage, to show the proportions. The barrel is the wrong way round, but it gives an idea.

Perhaps I am asking too early, but what sizes do others use for blocks and rope on the guns? I sometimes find blocks on models look very large, but from my own photo I almost get the impression that this block looks a bit small. Or can that question only be answered once a gun is fully rigged?

Hans had the answer ready: for guns the blocks were around 15 cm, he had once read somewhere. At 1:64, 64 x 2.3 mm = 14.7 cm. That fits exactly, so for once my lucky guess was right. Hans added that scale remains a tricky thing: very often parts are simply too large, but you come to see that as normal. The next day Jan posted another photo of a gun on the Victory, which shows the proportion of the blocks to the gun carriage well. According to him mine look very realistic.