they should work Mick. radiator hoses are manufactured on the american scale which means imperial measurements.( moulded hoses are sized different) 1 1/4, 1 1/2,1/34, 1 7/8, that sort of thing.
The rubber is nitrile thus resistant to hydrocarbons and a heat rating of 100 c. Your local industrial hose supplier will be able to sell you a few centremetres for not much money.
silicon hose is damn expensive and there are a few different types of silicone. the Turbo hose usually coloured orange would be the one to go for but talk the the bank manager first.
Many years ago i built a buggy and used a bent rad hose as an intake manifold and it worked pretty good.