Tube rolling Manley Shrimp

Has anyone improved, at least in their opinion, the sound of the Manley Shrimp by changing the tubes? Open to suggestions or if the tubes supplied seem to render the best sound to stick with them. Thanks.
I replaced the signal tubes with Mullard 4024s early on and felt that the sound became a bit warmer. As to the output tubes, my unit came with GE 7044s; I later switched to some Tung-Sol 5687s from the mid-'50s, but I don't recall this having much effect on the sound. In any case, this combination continues to work well for me.
Thanks. I've always had great respect for the warmth of the Mullards and I ordered some CV4024s when I ordered the amp as well.

Was thinking of something along the lines of a Mullard E182CC in place of the 7044s or 5687s. Amp just arrived yesterday and I will listen to it for a while before I start changing tubes.

Thanks again for your input.
The NOS Mullard 12AT7WA / CV4024 are the best (regardless of money I think). I use the in my Stingray. World will go crazy hunting them when the old stock runs out - look what people paying for NOS Mullard CV4004/12AX7 right now!