Slightly off-topic, but regards steel balls have you tried this company Simply Bearings Ltd ~ Oil Seals SKF *** TIMKEN KOYO NTN NKE TRULOC Needle Rollers Taper Rollers Rod Ends Oil Filled Bushes Loose Balls O Rings Grease Plain Thrust free postageHey mate can't exactly tell you which videos to look at specifically but Wayne Martin (CattyShack On YouTube) only uses 11mm steel and 10mm lead. I only use 8mm steel for hunting and target so I can't give great input as what to use from personal experience, but can give a some what educated guess based off of what I used to shoot. I would say for 11mm steel for either hunting or target, would require a single band from a .75mm thickness up to a 1.0mm thickness. Personally I would start at a .80mm and go from there. Tapers most commonly used for bigger steel and lead include; 30/25mm (Lighter band around .65mm / .70mm thick), 27/22mm (Band around .75mm / .80mm thick), 25/20mm (Same band thickness as 27/22mm with the exception of .85mm thick) and 23/18mm for bands between .85 and 1mm thick. Personally I would not go any lower with tapers unless a 20/15mm taper for targets, even this would probably not be very quick with 11mm steel. As for brands, sumeike, sheshou, great white, precise, BSB etc are all fairly well known brands. That only covers the flat band side, there is still single and looped tube setups that I can not give much info on. That is all I can say and hope someone with more experience shooting larger steel gives you a better insight into setups.
Simply bearings I use seem great. Low carbon balls are the only cheap ones but that doesn't matter.Slightly off-topic, but regards steel balls have you tried this company Simply Bearings Ltd ~ Oil Seals SKF *** TIMKEN KOYO NTN NKE TRULOC Needle Rollers Taper Rollers Rod Ends Oil Filled Bushes Loose Balls O Rings Grease Plain Thrust free postage