The larger cylinder just does fit under the cases. Fortunately Honda molded a cavity in that location for the cable to pass through. This bigger cylinder fits snugly in that area. Two drawbacks I see are: 1) the cylinder is in contact with the lower case which could cause some heat transfer. How much i don't know and if it would eventually affect operation given the hydraulic fluid within the unit or the longevity of the rubber on the piston. 2) Installation of the cover is more difficult as it must be rotated on one dowel pin to place the slave iinto the case recess and then clocked back to align the bolt holes. In my situation, I'll probably remove all of the locating dowel pins so this becomes a non-issue. This is a dragbike so the cover riding on the shoulder of the cover bolts is not a deal breaker for me. This cover isn't stressed in a manner whereby a lack of locating pins will adversely affect clutch operation. The slave cylinder itself pulls against the cover, nothing else.
The only other thing that could be a problem is the hydraulic line routing at the cylinder which is near the exhaust. As the picture shows, the fitting must be tilted at a 30- 45 degree angle given the odd shape of the cylinder in this area. I really don't think it'll be to much to worry about on my bikes with the sidewinder but a bike with a stock exhaust could have the pipe closer.
Since we don't have the luxury of grinding material from either this slave cylinder or the cases, any of my above listed observances need to be taken into account as i move forward. Honestly, any or all of these items will likely become mute points. The only simple solution to eliminating all of those concerns is to try using the smaller bore slave cylinder as it leaves just enough clearance away from the cases and allows the hose fitting to be angled in more ways. I prefer to give this larger cylinder a shot and will remove both dowel pins.
I'm moreso encouraged now to give this clutch setup additional time and effort.