Basically I have never played the Monk Class despire hundreds of hours in the game and I have heard good things about the Forbidden Fist+Trickser; I want to use the Magistrate's Cudgel in the main hand and Tuotilo's Palm in the off; does the main hand have to be unarmed or can it a weapon?

Tuotilo's Palm is "unarmed", and can work with everything in main hand. 

Yes, you can use it with a weapon in your main hand or just your fist. It counts as an unarmed strike so it benefits from Transcendent Suffering, which makes it the best shield in the game if you're a monk, since bashing shields otherwise do not scale with damage, ACC or PEN, and thus quickly become mediocre weapons. It also benefits from BOTH the weapon and shield and dual wielding talents, so it's worth taking both. For a monk, you'll definitely want the Balanced Shield upgrade, since it gives you a great boost to defenses based on the number of wounds you have. As for the other upgrade, it's up to you, but if you play on PotD difficulty you'll want the bonus to ACC.

11 minutes ago, dgray62 said:

which makes it the best shield in the game if you're a monk

also the best shield in the game if you're a non-monk but a class that (can and does) pick up monastic unarmed training

Since it's a shield and a weapon I think it also benefits from the two weapon fighting talent as well as the shield talent. So if you're using it it may be to your benefit to take both.

Thanks for the replies!