SquirrelHeart - as with any ML, slug the bore if possible - if not, then pick a descent ball diameter and strip of patch material. Lay the material over the bore and punch it down into the bore 1/2" below the crown, then pull it out with the 'tags' of cloth. Check the ball's sides for markings, light from the groove and heavy from the lands. This is how I determine if the patch will seal that particular ball. If there are markings only form the lands, the combination is usually too loose and the patches will burn out giving poor accuracy and dirty shooting with fouling buildup. Test a thicker patch or larger ball and try again.
As to loads, normal stuff for any gun. In the little ones around .30 cal., start at 20gr. and go up in 5 gr. increments - so, 20, 25, 30, 35, 40 - maybe even 45, but not likely you'll have to go that high. In those 5 loads, you should find the best one. Due to the small bore, further finetuning might be necessary - like 1/2 way between 30 and 35 = 32 or 33 maybe, maybe not. Larger bores will show slight difference in 5 gr. increments, so small bores should show similar change with smaller charge differences.
Range is another consideration- what range are you shooting - 20 or 25 yards, 30 or 40? The longer the range, the 'better' must be your load. By 'better' I mean the load must be more highly refined in the accuracy department for that particular rifle to be accurate. Most rifles will shoot into tiny groups at close range- 20 to 25 yards, yet that same load might shoot pie plates at double that range - testing and experimentation is needed to find the 'best' load.
Your .30 will probably shoot best in the 30 to 40gr. range. if you are getting fouling buildup, go to a thicker patch, better or more lube. Ordinary spit is one of the best patch lubes there is - it works in ever muzzleloading rifle I've ever shot - patch must be saturated with spit - simple loading and shooting. Wiping at any time should not be needed - if it is, look to your patch material, thickness, ball diameter or lube type and quantity.