If you’re using software monitoring; latency can be adjusted by modifying the size of your input buffer. You’ll find under the audio section of Logic’s preferences. The lower the buffer the less latency you’ll have, but the less stable the software will perform. The general rule for using software monitoring is to use as small of a buffer as you can get away with. I never monitor through the software if I can avoid it.
If your GK and Focusrite units are giving you wildly different levels of latency I would be sure that you’ve downloaded and installed the latest version of the drivers/mixer software for each interface. Also, as a good practice, if you’re monitoring through the software you should try to keep your session as clean and free from plugins as possible while tracking if you want to reduce latency. It’s also worth doing a loopback test using the I/O plugin to be sure that your system is calculating the correct number of samples to offset recordings by for accurate placement of recorded material.