Howzit
As this site is predominantly a surfski site you would find that most would plug skis.
As for what ski, this is dependent on your situation ( previous experience in a ski, seat size etc). Would you be wanting to race or are you happy to paddle socially are questions you should ask yourself.
There's no argument that the ocean racing skis ( Fenn, Epic, Icon, Robberg, Huki plus many more) all out perform the spec skis. Unfortunately these bring along their own challenges such as stability issues.
There's no shame in starting on a stable ski and moving up to the molakai type ones later.
And Yes, I have seen a few 120kg guys in Epic and Fenn skis.
As for your goal I believe it is possible provided you are comfortable and paddling fit. Get some training advice from the local ski representatives ( Huki, Epic ) or post a message here tips. I'm sure you will find many very happy to help.
If you can paddle with others it is not only safer, but you can all share the pain which is easier.
Cheers
Martin