All transitions use the same BendTimePowX<> function for accel/decel. If you’re having difficulty with the syntax it may be easier to wait for the Style Editor to be updated.
You’ll want to use the X version so that you have replaceable functions.
So if you look at TrWipeSparkTipX in the current style editor, hit the expand button to break it out to it’s full form. You’ll see it’s a TrJoin running a wipe and a spark simultaneously.
The wipe time milliseconds and the Spark MS are the arguments you want to make bend time
compare this to what you have InOutTrL<TrWipeSparkTipX<White,BendTimePowInvX<Int<1000>,Int<180000>>>,TrWipeInSparkTipX<White,BendTimePowX<Int<600>,Int<180000>>>>,