How does the mag crankin stick handle 3-4 oz lures? Thinking about using it for deep cranks and light swimbaits.

how does this handle the 6xd? 

That Mag-Heavy Crankin' Stick with a 1 - 4 oz rating is a new addition to the line, introduced in the past year along with the rest of the redesigned Crankin' Sticks, so it may be that no one on the board has any experience with it.  

 

All I can contribute is that I have a 7'6" MH Crankin' Stick of the previous generation, with a lure rating of 3/8 oz to 1 1/2 oz, and it has no problems tossing baits in the 1 oz range like 6XDs, BD8Fs, Little John DDs, etc.