The 630 garage is more of a storage area with a largish transom door. It is nothing like the garages of the 575/588 or 675 which are specifically designed as a garage which can launch and recover likes of the Williams jet tenders and standard RIB tenders. To launch and retrieve the jet tenders an optional winch is required as is an optional roller system. 

The 630 transom door is well above the water and the storage space is orientated across the hull rather than along the hull in the case of the 575 etc. The 630 garage is more suited to a small light weight RIB or a larger (but still light) inflated with an inflatable floor. I would think there is no way to get a Williams jet tender into or out of a 630 garage.