I'd recommend this, as I have done it! Take the old hoses to your local hydraulics engineer and they'll make them up on the spot. When you do, get 45 degree fittings on the cooler and work out for yourself which is best for the other ends (setups vary here, but I had a 45 where the hose went to the radiator, and a straight coupling to the hose alongside the engine). Total cost was about £80, which seems about right.
If you look in the Tech Archive you'll find a guide that will point you in the right direction.
When I did mine, the cooler was *just* able to be mounted in the old horn holes, and the horns in the old cooler holes, it makes it tight at the top, but not restricting airflow in any way, and leaves space for a second cooler should I ever need it.
Credit goes to Adrian and White90 of course!
HTH,
Bowie.