i would say shimrra would have a hard time dueling grievious bc of his 4 lightsabers and the 20 strikes per second thing.
when it came down to a fist fight, bc i have a feeling it would at some point, i think shimrra would eventually win here bc he is the most powerful and largest of all the vong species. grievious would put up a good fight though bc of his 4 arms and most of his body being made out of metal, hard hittertongue_smilie
The General. Shimmra's amphistaff would have a hard time dealing with Grievous' four blades coming at him from all different angles and speeds.
In a fist fight, Grievous also beats him down. Shimmra might have been big and imposing, but I don't remember any strength or unarmed skill feats that compete with Grievous punching through durasteel hulls and killing companies of clones with his bare hands.
well i know this is just an assumption but shimrra was considered the best fighter of all the vong warriors and even the vong slayers, who were all skilled fighters.
it took luke at the level that he was at that time to beat him, although luke was probably alittle drained from having to fight several vong slayers.
also luke held his own against several slayers without really using the force and beat them by using the force, but kyp durron had a very hard time beating just one of them and his force potential is considered close to luke's.