For some explanation, I currently use a 2019 Kosmic that’s setup for comfort. Not ideal I know, but I’m relatively new to the sport (1 year as of writing) so I knew that no matter where I put the seat my biggest time gain was in driving. Now however I’m having issues with my current seat and my hip width so am going to switch to a T11 Wide hip. I’m 6’2" and have the seat quite far back to keep my legs down, but now I’m having the issue that, when coming out of corners, because all my weight is on the rear my engine cannot get power down adequately out of lower speed corners (Rotax Senior Max) and when I try to drive differently to mitigate the problem (for example getting on power earlier) the kart starts hopping. As well as this I’ve been told having the seat this far back can cause these problems however I’m wondering If I switch seat rigidity will this help weight transfer off the axle for better acceleration and to stop hopping?
I think going to a softer seat will help these issues however I will have far less of an idea what I’m doing that what you all will, so any input is greatly appreciated, and sorry for making you read that paragraph of an explanation 
(Edit) - my current seat is a Jecko Silver Standard