Heavy 9mm reload recomendation

I've go a buddy that picked up a new S&W 986 and it favors heavy bullets. I'm looking to try 158gr bullet. Barrel & throats have not been slugged/measured for sizing yet. Figure I have some room to play with the OAL length in the wheelgun since I don't have to deal with a magazine and he is looking for accuracy over velocity. I'd thought of trying to run a wadcutter poking along at 700fps out of it, but that would just look wrong. Powders he has on hand are red dot & 700x.

Any recomendations for a starting point from experience?

From my experience working with heavy boolits in 9mm semi-autos, I think you will find Red dot and 700x to be less than optimal with heavy boolits. You can achieve the light load you were thinking about but if you want faster you will need a slower powder. Something like Longshot or AA7 would give you more options.
Since you don't have to worry about working a slide, you can go as slow as you wish. With slower, light loads, the powders you have would be fine.

Accurate 36-155D cast of wheelweights, sized to cylinder throats, crimp in crimp groove, 3.2 grains of Bullseye, groups better than factory in my 9mm Ruger Blackhawk convertible and Police Service Six 9mm.

I use a 140 grain round nose bullet with Bullseye powder. Start around 3.9 grains and work up from there.

Thanks for the input guys....

I found a listing for Red Dot used with a 147 grain XTP in an older Alliant manual. It listed 3.4 grains as max.
The Hodgdon data site suggests 2.9 grains for the same 147 grain XTP with a starting load of 2.6 grains using 700X.
You would need to start well below these numbers for the heavy boolit you want to use. I can't make a specific recommendation for the boolit you wish to use.
The velocities with the max charges were listed as being in the low 800fps range. With your heavy lead boolit the numbers would be slower yet.

Years ago I ran a LOT of 158gr LRN out of 9mm through a suppressed subgun. (So, obviously, they were loaded to magazine length.) The load was 3.3grs of Red Dot. This was with the old, dirty-burning version, not the new, improved version from Alliant, so you may want to back off a bit and work up. It ran like a top and was plenty accurate (though I never put it on paper for a group).