Yes, I am running SRAM grip shifts with an old Shimano SIS derailleur and Shimano 7-speed freewheel. All your doing is pulling the derailleur over a specific amount of travel for each cog of the freewheel or cassette. As long the shifter twist pulls the cable the correct amount to line the derailleur up with the cogs it must shift correctly. If you're having trouble then something is incorrect with your shift system. A common problem that can effect the shifting greatly is cable drag due to excessive friction. Pull your cable casing off and look at the cut ends. More likely than not there is a small bur that is dragging on the cable that needs to be removed. I use a very small blade on my multi-tool pocketknife used to punch holes in leather and other materials to remove that bur. Proper dressing of cable casing is a must that no one does and causes so many shifting problems. You must also cut the casing the proper length between the shifter and derailleur where casing is required. Too long can be just as bad as too short! Worn out or dry (dried up lube) index shifters also cause problems. Grip and thumb shifters must be lubricated at least once a year. You can test your shifting system by removing the chain and putting a dial indicator on the derailleur. This allows you to measure the derailleur travel for each click of the shifter which should equal the spacing of the cogs on the freewheel or cassette. This can be done on a workbench if you just want to test a shifter and derailleur before you go to the trouble of installing the parts on a frame. If you know how to use a dial indicator then you also know how to set it up! It's nothing more than a simple pantograph after all.