Also I think I have the 250 g2. Someone pointed that out in the beginning of my post!
I will tell you the only roller mat I was able to fit was the reef mat 250. It’s like the second smallest one they make and the thing HARDLY fits. I don’t know if the dimensions of the sump for the 200 are similar to the 250. When I look at pictures of the 2 tanks they look very close in size.
You could try the drop in filter roller tho. The ones that sit right in the where the sock would. I just don’t know how good they perform compared to a little bigger one.
If you do decide to cut the sock part out I’d use some sort of hard wire or maybe some sort of very strong fishing string because cutting it with a razor blade was a pain! They did a pretty good job at siliconing stuff in place

. Also, I’d get this part done when it’s still dry.
It is just my opinion but if you decide to do filter roller I’d probably change out the ball valve to gate value. I was not able to keep the water level stable in the overflow. The thing was so loud it would wake me up lol.
Depending where you live might be challenging getting the correct size gate valve. I live in the United States and finding metric parts was difficult for me. I know you could probably use conversion adapter but I chose not to do that. I ordered the parts off
amazon and it took forever to get here.
My last tank I used a Clarissa and I think the rolled lasted much longer than the Red Sea ones.
Overall the filter roller is doing well tho. It was a must for me after the last one I owned. In a perfect world I wish the Red Sea may lasted longer or I could fit the next size up in it. I could probably lower the flow through the return pump or divert water through the emergency drain to make the roll last but I’m choosing not to.
If you have any other questions please don’t hesitate to ask! Also hopefully some others share their opinions as well!