Centaurus,
I think this just goes to show what a wide range of SOPs there are in different airlines and that there are many ways of achieving the same end.
On a slippery runway with a crosswind the FCTM advises that reverse might have to be reduced to idle to prevent further yaw into wind then re-applied once the aircraft is straight.
Faced with a
slippery runway
and a significant crosswind, I, for one would retire to the bar and watch others' efforts through the window with great interest.
IMHO, with very low braking action, the critical part of the takeoff is actually the slow-speed end, just above taxi speed, where there is little to no aerodynamic control. If you don't get rid of thrust asymmetry rapidly, you're off the paved surface.
If you've decided that you *are* going to launch from a slippery runway with the breeze off to one side, then I would sincerely hope that the briefing had covered these sort of eventualities and everyone involved was sure of what their action(s) might be. Under our SOPs, it would be a call of "Reverse idle" from the HP, or, in extremis the HP would do it themselves. Just because normal operation is to split these duties doesn't make it "forbidden" to do it another way if it seems the safest course of action at the time.
The rejected take off decision is the captains responsibility entirely and he should have full control of all the flight deck systems that are required during an abort. That means the brakes, thrust levers, speed brake and reverse thrust levers. He then coordinates his actions on each of the systems to achieve a safe result.
Note: Personal opinion only but backed up by reference to the manufacturers recommendations
As I pointed out before, manufacturers' SOPs are written with the lowest common denominator in mind - and that's pretty low, if fact more of a single-pilot operation. When you have a well experienced, trained and checked aviator sitting next to you, it would be counter-productive not to involve them in the operation, just in terms of resource management. As
Hand Solo intimates, when RTOs get cocked up in the sim it doesn't seem to bear much relation to how many stripes the pilot had on their shoulders at the time...
Why would you override the RTO selection of autobrakes when it already gives you max braking.
I included that option for completeness - of course you'd leave them in but there are situations where the autobrake may disconnect or perform poorly. Below certain speeds on most aircraft, the AB isn't armed, so you could go quite a way down a contaminated runway before realising there wasn't any braking at all! We include this item in our pre-takeoff briefings just so we remain alert to the possibility of malfunction and the fairly urgent need to do something about it - it certainly isn't SOP to disconnect them.