I only had a Grizzly Squirrel and I assume its slower than a normal squirrel because it never lasted long enough to even apply Nut Barrage using this strat So if you're in the same situation somehow...!
I personally just used 2 375-speed rabbits and my slow-az Grizzly Squirrel xD
Bunny 1 > Dodge > Stampede > (Dead) > Bunny 2 > Dodge > Stampede > (Your bunny should be alive but is switched with your squirrel) > Nut Barrage > Adrenaline Rush > Nut Barrage > (Dead) > Bunny 2 > Dodge > Stampede.
You need to be a bit more explicit than just a TDScript. The beetle has 4 breeds with 3 different health pool sizes and the squirrel has 5 breeds with 4 different health pool sizes. As it is everyone has to mix and match until they find one that works with the rabbit's hp size.
This one eventually worked for me. A little bit of RNG on how hard Mar'cuus hit with some of those portals and pounces. It helped for me to use a H/S breed bunny (Arctic Hare in my case). My P/S Dust Bunny got wrecked too quickly and didn't work in the second spot as a result.