Once you determine the proper location for your seat position
The spreading of your seat struts will be a piece of cake, as your chassis is super soft, you really only need about 1 to 2 inches maximum on each side.
Just be careful not to crack the bottom of the seat mounts, where welded to the frame rails, so gently support at the bottom and midway while you bend it.
I would not use a cheater pipe, as it will scratch it, rubber hammer works best as an attitude adjuster.
Just do a little bit at the time, patiently, take your time on each side, and try the fitting the seat till you’re closed enough.
Put a straight bar across the bottom of frame rails, from left to right ( under seat) So that you don’t go past/below the frame rails causing major drag of seat on the track.
So, honestly the hardest job will be to find out the best measurements for a Rib Tech seat on a Tony Kart, between axle and back of seat, inclination of seat, and how close to the fuel tank uprights you need to be.
Once all that is into place 100 % then you can start drilling holes.
Don’t be afraid to do it, you can do this
And remember, Most guys with a lot of holes on their seats are very fast. My 2 cents. Fast Freddy;)