I use the pre wired distributors on my engines....and I have been accused of being a rivet counter.....with that being said, I think part of the problem is more with the kit manufactures than with the builder. I am not familiar with the web sites that Rich Sipos speaks of, so I am not going to comment directly on those particular builds, but to get ignition wires that look like water hoses, I am assuming the hoses between the block/water pump and firewall, they would have to be 1 mm. or perhaps a slightly larger dia. in 1/25th scale. The largest dia. plug wires that I am familiar with are 9.9 mm. (1:1 scale) Accel, Moroso, Mallory etc, etc. which measure 3/8" or less than 0.50 mm. in 1/25th scale.
SHAMELESS PLUG... I use the Morgan Automotive Detail pre wired distributors.....the distributors look like real distributors...not simply a round piece with some pieces of wire hanging out. The plug wires measure 0.47 mm. which is right on the money as far as I am concerned.
As far as a distributor looking right with the rest of the engine, I am going back with what I said earlier in this post about the kit manufactures being partly to blame. I cant comment on G.M , MOPAR or any import engine sizes and dimensions but with Ford engines I have amassed quite a bit of info. over the years. I have, what's supposed to be small blocks, that in size are almost as big as a fat block 427 and visa versa....big block 429/ 460 engines that could be easily mistaken for a 351 Cleveland. I have seen kit distributors that where either way too small or excessively over proportioned......so it is quite plausible to have an accurate, aftermarket distributor that looks too big or too small with a disproportionate sized kit engine.