Pretty much the same as me then.
I expect you have a .22 with normal length barrel.
I've had mine reduced back so that it is a couple of inch's shorter than standard length with the moderator fixed on. This enable more movement in the cab if wanting to switch windows or lay it to rest on the seat etc.
Also i have the lamp mounted on top of the rifle, set so that the beam falls centred to scope at 50yds allowing a shooting range of almost 0-100yds.
I have an additional .22 with a night scope so i can park up and shoot from any position including the roof with no lamp at all, but still have a light mounted on scope to enable picking up and still have use when walking.
So far as shotgun shooting, i used to have a cam net which was fixed inside a metal box permanently on roof with the poles. This was quick to set out for pidgeon shooting as a hide, and being on the landy, i could set up anywhere including middle of field, and still have my packed lunch etc at hand.
For hawking, i had dogs in back in a box which had a cadge on top. The roof rack was padded to sides both for them to sit on, fly off and too. Also doubled up for a gun rest when shooting.
If shooting from roof rack i used to have rubber matting, as used in stables, laid over the wire. Both for comfort and weather friendly.