The type of grease really isn't particularly important. Basically the thicker and stickier the better! I'd also caution against greases with a high molybdenum disulphide content as this can in fact build up at the point of contact of the rollers and actually promote scuffing. The main problem isn't the type of bearing or the loads applied to them and how they cope, it's mainly water intrusion and the fact that there's nothing coating the cage or rollers to protect them from it. While the seals in the frame are adequate, (As long as they remain on their registers!) the Achilles heel of the system is the rubber seal incorporated in the cone of the RS bearing itself. These are an odd design and while 30205RS bearings are available in the aftermarket the type and position of the seal on the center race is different on the ones Guzzi uses and their ability to actually seal in the frame is dependent on the outer race sitting below the frame spigot it's register is cut into. This enables the outer edge of the seal to sit recessed into the frame. Unfortunately though its ability to actually seal in these circumstances is a bit 'How's yer father?' and given they are in a pretty hostile environment unless they are well and truly stuffed with grease water ingress is going to be pretty much inevitable. The good news is that as long as you do get to them early and pack them chock-a-block, (Yes I know the conventional wisdom on bearing packing.) they will last pretty much forever. The first one I discovered with really badly shagged bearings, (Worse than Vic's!) was a 2008 1200 Sport. At 40,000-ish Km they came out in big ugly chunks! They were replaced and packed well with some sort of marine grade 'Waterproof' (?) grease and the next time I saw them was when the bike came in for a 180,000km overhaul. They were re-packed and went straight back in! This is a bike that is flogged mercilessly, mostly two-up and with lots of luggage. Since then I've done several more with similar damage and later checks reveal the success of decent grease and packing. Like most things about Guzzis they are well up to the task and tough as old boots! The problems they have are down to shitty assembly and or neglect.