2wd buggy tyre insert advice

[The Dark Knight]

Can anyone offer me some advice on 2wd buggy tyre inserts?

I'll mainly be racing on cut grass at my local club so this is what I'll be setting the buggy up for.

I've bought Schumacher mini-spikes in yellow for the dry front & rear and Ballistic buggy mini-spikes in green for the wet front and rear.

I've been advised to get medium inserts, so I went for some closed cell medium inserts.

Now here's the dilemma I am having, the 2 sets of closed cell medium inserts I've received are slightly different even though they are the same brand. One set has a groove in the middle on the inside of the insert which give the tyre a slightly softer feel.

Am I better fitting the softer feeling inserts to my wet tyres or dry tyres?

I haven't used the buggy yet so I can't comment on how it handles at the moment.