Tonka,
Sent you a PM mate.
I would look at a set of leads from a Pick a Part or similar place that have these rubber spark plug well sealing caps already on them, that fit your motor. Maybe you can cut these off, very carefully, and stretch them to fit over your plug leads and slide them into the spot you need them????
Not completely watertight but a huge step in the right direction.
Perhaps finish them off with some black silastic sealing goo???
Mitch.