Slap the 3 low capacitance MOV units in, and be done with it. The limiting factor will be the PTC in any case, 1kV and it will fry itself apart in a second or so. Choose the voltage to suit your normal use, and as they mostly come from RS in packs of 10 you will have some spares. If you do blow them up the meter will not survive in any case.
In my case I just used 2 275V MOV units ( 7mm) in series, as I did have the remains of a 10 pack around, so using the 6 was easier than either placing an order and wait till I had the minimum order price in other parts, or paying the $20 courier charge RS puts on here for small orders. Still have 1 left, after replacing 3 MOV units on other equipment.