Though looking at it anothe way
1. A lot of castings are overpriced and a complex part can be found lurking within a cheap to buy lump of metal.
2. Although there may be gold in some of those cheaply obtained items some can also be as hard as diamonds and will trash your tools
3. You always start with a luimp of metal that is big enough to get your part out of or join several together
4. Wonky cores are avoided by starting with solid material
5 You can allow whatever extra length you want to chuck the work by
6 As above its there until you cut it off
7 No need for jig see above.
You also missed out
8 The foundry may have removed half your casting by over use of the grinder/linisher while fettling the casting
9 They may have given you that extra feature of a step down the joint line when the mould shifted
10 You may have been given a suprise hole or sand inclusing that will only appear on the final finishing cut
11 Some incompetant may have had a go at the castings before you this relates to point 1
13 Previous owners may have lost parts of the set or used them on other models this often applies to flywheels
12 You are limited to making models that are not unique and just have to follow others lead
14 Just because they are castings does not mean the engine will run.
J
PS Talking of materials did you know that engine we were talking about that I bid on has Elektron castings, I'll let you google what that is
