Just answered my question myself with
http://forum.supercell.net/showthrea...ry-Revealed!!!
Leaving (5) cannons at level 9 and (3) teslas at level 5 opens some nice possibilites compared to a 'normal' T8.5 from maxed T8...
1: get the 4th AD (level 6) + 4th Tesla (level 5) + 2nd airsweeper
2: get 2 x-bows (level 1! don't upgrade)
3: upgrade 2 mortars OR 2 wiz towers OR 1 each to 7
calculated with new traps, upgrading all air traps and skellies to max, small bombs at level 4, the total base wight is almost the same, may vary about 100 points in all cases. (from about 50.4k (in my case with troops and stuff))
The one interesting point about option 2:
does the matchmaking only include the pure numbers of a X-Bow, or does it also include a 'X-Bow yes/no' thing to balance war wight?
The numbers itself are much higher with maxed T9 splashers and no X-Bows than with T8 splashers and X-Bows at level 3. But a X-Bow makes another change to attacking troops and stuff...
keep in mind, this was
pure theory crafting based on spreadsheets linked above.