Most of it should still be applicable to your box as the A342 and A340 should be quite similar.
You may notice an improvement by using Toyota Type T-IV ATF, as it is specially formulated for certain Toyota autos. Dexron can actually be bad for some variants of the A3xx gearbox family apparently.
By the way, isn't the handbrake part of the rear disc assembly ? If so, trying to lose traction with the handbrake on will be a lot more of a challenge for the gearbox (and likely to cause damage).