I'm doing an ABS to cast transition. 4" cast connected to a 4" to 3" ABS bushing. The bushing has a spigot end that should be identical diameter to 4" ABS pipe, so I figured a regular hubless 4" shielded coupling would work. (I used this one: https://www.americanvalve.com/product/rnhhd/) Problem is, the diameter of the cast seems to be slightly off - it's a slightly larger diameter than the ABS, to when tightened, the coupling shield buckles (since the ABS-side clamp has to be tightened more than the cast-side clamp). I poured some water down and it doesn't seem to leak - but it doesn't look to pretty (pic below). Is there a better coupling for this? Also wondering if I can wrap the ABS with a bit of sealing tape to increase the diameter to better match the cast?