Messed around a little last night and mounted them to the bike so I could see where would be best. Hooked up just 1 to power so I could see them in action. To my eye and the quick pics I took with my cell phone so I could compare,, the M61 looks to have about the same size and brightness of the model 30 beam with just a touch less spill light. Bigger reflector looks to make up difference in raw lumens ( 1500 for model 30 and 900 for model 61). Of course I'm just going by what I saw on the door of my garage and I have not done an outside test to check out total distance.
They mount up good and solid and I like the way they look. Here they are mounted to handguards, hanging down.
Mounted to guards but on top. I attached a model 44 below one of them just for fun and to see what it would look like. A little to clunky for my tastes but I bet the light output would be awesome with a set up like that on each side.