Block Wood ...Soft wood works best.(which can be shaped
)...held in place with Bungies or similar
Lowered Hydralicly onto wood Block (till it "Bites") and strapped down with TWO Straps ..friction or ratchet (don't over do it!) one on each side just above or below the Cav plate (whith two straps pulling in both directions and attached each side of the Trailer it counters side way stresses too) engine on its side (full lock) around 1/2 way up ...
This I've found to be the best way to take stress off Rams and engine lock/locks ect which are often woefully inadequate for towing ...especially with a Big outboard.
I have Towed a Heavy 250 HP Suz many 1000's of miles all over the Country....on good AND Bad surfaces!..
..Bear in mind the higher the engine the more stress on the Transom.
Check Straps Trailer Tyres and Bearings at regular intervals!