RE: ISonic fine tuning (For Ian and Kevin)
There a really are a lot of significant variables that will influence the "ideal" setings for downhaul/outhaul/boom/mastfoot (even on specific sail/board combo/s). Depending on the individual rider (height/weight/stance) plus personal settings like harness line length, fin selection (tuning and style), the water conditions (flat thru to extreme chop), wind (steady thru to super gusty) - and then the type of sailing (slalom racing [requires acceleration as well as speed] - pure downwind, or Fig 8 [with some upwind leg], hi wind reaching [blasting] or downwind pure speed GPSSS style [only concern for highest absolute speed, not upwind nor accel] ...and so on) the ideal settings will definetly vary.
In general, the CR responds best to medium to strong downhaul,but not to the point of totally killing the sail and indicing twitchy handling. Outhaul usually varies from moderate positive (beam recah or upwind) to moderate negative downwind/broad/speed or in some case quite negative for pure downwind speed)
Boom again, moderate high (average) - depending on many of those variables above - a little higher in "ideal" conditions and a little lower in totally crazy (control) conditions can help - although the higher position exerts more leverage over the rig in higher powered conditions, too.
Mastfoot placement is pretty easy, just bang it in the middle of the track (on those boards, with those sails ) and you won't be far wrong. Beyond that (again, really dependent upon many of those variables - and even fin choice in speed sailing can alter ideal stance, which in turn effects both mastfoot and boom height etc) - if you do need to move from centre, the general recipe is usually a little further FWD (2cm) in rougher or control conditions, and a little 1-2cm BACK for flatter water/higher speed.
Hope this all helps, well a little, anyway.
With some more detail specifics, it becomes a little more practical to offer (accurate) finer tuning tips - let us know !
For the bigger sail than 7.7m, typically the best size jump "up" would be the 9.0m in CR-R2. 8.3m actually works really well, and especially with the iS111 but is a fair amount of overlap with the effective range of the 7.7m in normal use. Considering the range of both the board and sail, if getting the most range from the next sail is the objective, then 9.0m is the upper practical limit (assumes less than heavyweight rider).
Cheers ~ Ian