Muzzle loaders have a bigger tolerance than cartridge guns so what works well for one may not do so well with an other, with the Knight the barrels are usually between .498 and 502 this indicates that going by size the MMP 12 or MMP HPH 24
or the Short Black Harvester [or the long depending on what bullet] are the best to try starting out. The MMP HPH 24 and the Harvesters mentioned are the same petal thickness but I have found that the differences in them cause them to shoot better with different bullets. It may depend on just how much accuracy you are trying to achieve. Some of us work for and get varmint rifle accuracy with our inlines.