Why? and why the common lead?
You will not be protected to 750 volts.
The max current will still be 1 amp.
What might make some sense is a 2 amp fast in series with a 1 amp slow. Not sure if that will have the desired result it implies.
I don't know how fast a 1 amp slow fuse opens when you feed it 2 amps.
No real reason to do such a thing. The 260 Voltage measuring circuit would never load enough to blow a 1 amp fuse. If you were measuring current the 1 amp would blow first. Seems an odd set up.
When Fuse is put in series , they are derated very heavily , if I recall there are graphs which has to be analized to understant the I2T for your combination.
The idea is that a cheap fuse will blow if the current is a bit larger than it should be, where the current is 10 amps or so, or where the voltage is small. This is quite common so it is convenient to have a cheap fuse.
If the meter is used incorrectly, and left on amps and connected to a high voltage supply that can supply thousands of amps, the is a big risk that the cheap fuse will not stop the current. The short circuit current can exceed the Breaking capacity - Wikipedia, the free encyclopedia of the fuse. The current continues to flow across an arc where the fuse used to be.
This is when the expensive fuse blows and saves the user's life / sight / eyebrows.