AI difficulty in dry and wet

[WestHam66 56]

Like quite a few players of F1 2019, I've found a discrepancy between the quality of the AI in wet and dry conditions. The latest incident of this for me was the last race I did in career mode. At Monza, I qualified 9th on 74 and knowing that the AI improves in wet weather, I turned it down to 70 for a race that would be wet throughout.

I came 12th after a poor start and having cars all over the back of my car for most of the race. Fortunately, it isn't too hard to defend at Monza, but a made a couple of mistakes, which meant AI cars passed me and I wasn't able to catch up. On the first few laps, the cars in front were much quicker than me, so I had no chance of making up positions after the first few corners.

I'm not particularly slow in wet weather, just average.

By how much should I turn down the AI by in order to negate their improved pace in wet conditions?