Three points perhaps worthy of note:
1. You asked whether it may be useful to tweak the DOSBox configuration file. It certainly can't hurt to fiddle, provided that you back up the original file. Pay especial attention to the [cpu] section. Mine for Daggerfall reads as follows:
core=dynamiccputype=autocycles=autocycleup=5cycledown=5
Try running the game with these options. Some people find that
cycles=max works better for them; give that a try too!
2. Bear in mind that it is often normal to experience slower gameplay with Daggerfall on a modern computer than with, say, Morrowind; this is because you're running through an emulator, which is inherently slower than the native platform. Reports have it that Battlespire, for example, is frequently very laggy in emulation via DOSBox unless running on a top-end computer. Hopefully playing with the configuration will make it a bit easier for you to record video whilst playing.
3. Since I didn't seem to find anyone mentioning it, and admittedly it is a bit of a long shot, I though it may be an idea to try playing the game with a different reflex setting. Make a few new characters and see whether playing on different settings does anything.