Hi, I'm planning on trading the S&P 500 emini contract. Starting with small capital, naturally I want to maximise my leverage. Therefore, I have decided to use a spreadbet service.

However, I have been strongly advised to trade the full contract; I think because the spreads are tighter. However, if I did trade the full contract, I would have less leverage than if I was to spreadbet, where the brokerage/spreadbetting firm would act as the market maker. So whilst I might even lose 0.25-0.5 pts per trade, I think spreadbetting is definitely the best option.

Only if you make money. If you lose money, the option without leverage is much better value :-)

Yes, but one assumes that one is managing one's risk accordingly.