Construct a wind-star at the same time as writing up your PLOG.
Assuming you use the wind-down method, spin the computer round to the 8 compass points, and you can directly read off your groundspeed and drift angle.
Write them down somewhere on your kneeboard for reference.
(16 numbers sounds a lot, but it only takes 30 seconds to do this)
When you do the diversion, just look up the closest one to the direction you want to head in, and use that correction angle and groundpseed.
(Or you can estimate between the two nearest values for more accuracy)