ReqVG of Max Flash should be 1 and OP should be 2,000 depending on multiplier you want to achieve. With this setting, my max flash links @ 20% chance. Even after raising the max % cap in ps_game( from 50% to 100% ofc). To make the hammer have a higher or lower multiplier, then you would edit the reqVG. Try checking all of your hammers settings and toy with numbers til you find % you want for each hammer you will end up using. Good luck, I'm sure you can figure it out from there. Good old fashioned trial and error does help!
For a few more tips, and guidance try this out:

Give Thanks to ProfNerwosol for Guide:

Another Topic about linking percent/chances can be found ::

:: as well.