Welcome to the new site
"I tested a lot of slalomboards during the season. Also the sonic 85 and isonic105. The 85 really convinced my with 6.0 GTX and high wind conditions (20-30 Kts with gusts over 35 Kts) with the board staying controllable and very solid. The iSonic105 I tested with too small fins most of the time (32 cm) which didn't give a very proper view to me."
It's pretty fair to say the iS105 has been rather convincing in top level competitions to date, and a lot of times 32cm would have been the fin, so it really comes down to testing (or racing) the board tuned in optimal for the conditions you're using/testing it in. I guess the point made here is that (in the correct conditions) 32cm is a very good size for top end iS105 performance.
"Which iSonic may be better for me (95 kg) in flat to choppy conditions for the Overdrive 6.5 for slalom and speedsailing? The bigger sail is an OD 7.5 and the smaller an OD 5.5 which work great!! The 7.5 will be used with my Falcon120 normally. The 5.5 I may use also on this board, but the 50 may look nice for the 5.5 and RS4 5.0!"
If you want to new board to cover the 7.5m also, then the iS94 would be a good allround choice, more especially if you have a special smaller rocket for pure speed. If you decide to abandon the idea to use a 7.5m on this (new) slalom board, but maybe at the same time have the (new) slalom board also cover you for speed in medium (less than true epic) speed conditions as well, then the iS87 will be a very practical compromise and would certainly be Ok still with OD 5.5m
(by RS4 5.0 /95kg conditions, well, you can imagine, even the 87 is getting a bit more than required..).
nb: the site is working better and better at the moment, but I can get any details at this time.
Thanks, we are working on that bug, there is also a thread (iSonic- Widths) in AskTeam with iS details for short term.
"Does the 87 and 94 have slide cut outs as well?"
No, we tested but decided to not use these at this time in these models.
"nb: does the 50 also has any slalomaspects or you always have to walk back (with I normally do at Strand Horst in the Netherlands (also with large boards) after making a dozen of speedruns to much)."
Ok, well it depends a bit on the driver, but the boys in The PiT will tell you that I'm not walking a lot, at least not while they are sailing by comparison. For 95kg, the iS50 has limited "slalom" potential but is definitely designed to be a very practical board out on the speed course, and to allow the rider to quickly, easily, efficently (not using excess energy walking or sailing) get back to the top and complete as many runs as possible in a session. Benefits of that are rather obvious
( a side note here for others is that for heavier riders especially, the iS50 does need some pretty good technique, moderate windy conditions and maybe some positive attitude to get the thing going, - it's NOT a F161 - but it WILL do it and when it does it's pretty sweet.
With a 95kg rider and 5.5m-6m sail , the iS50 will plane reasonably slow, as slow as 15 (even around 12) kts of BOARDSPEED (note! Board speed not windspeed) - which might seem and odd or unimpressive stat to most of you, but once you're on a true speed board trying to sail back upwind (and potentially thru chop) it's a very useful thing on a board with killer top end potential as well)
"How does it deal with small/larger chop (0.5 mtr<, what are the differences with the small isonics."
iS50 is designed for top speed in medium to perfect conditions (not just perfect), which in most good speed locations means rolling chop on broad course to (aprox) 30 cm in the speed run and more out the back sailing back up. At top speed it handles the speed course chop very well, on the sail back (in rougher chop ) the iS50 is very practical and "seaworthy" for asedicated speedboard, but it should NOT be viewed that the iS50 is killer fast thru open ocean chop or extreme confused chop (as often would be found in conditions where a 95kg rider is using a 50lt board ..) BTW, it IS killer fast in these conditions, emphasis on killer.
"Which sailsizes can the 50 handle easely?"
Basically the true speed range 4.0m - 6.0-6.+ m (pure race sail sizes) for adult top level speed use.
For 85-95kg rider, the sweetspot will be 5,5m (5x-6.0m currently I'm using CodeRed 6.1m very effectively, with on water weight 100kg), but my ideal size is probably 5.1m/5.6m.
An interesting aspect is that with a very well tuned sail (around 5.6m, for my size) this board will provide enormous practical (speed) range over a range of conditions with virtually the same setup.
Hope this helps answer these questions but welcome further discussion/s.
Cheers ~ Ian