Did the same thing to a Mustang seat years ago... Had a custom saddle guy install a 1/2" thick , blue colored gel pad (he had the gel, so don't know the type/brand).
First comment - It was more comfortable

Second comment - It got nut roasting hot, and held the heat for a long time, when left out in the sun

Not so sure the comfort was better than the heat...

Black Dog
Nut roasting hot?

Not good
You would be better with layers of good foam and memory foam.
Have to check that out.
I have a Mustang I owned for 12 -13 years and I like the seat, just gets hard after an hour or so, either that or my butt gets soft.
Thanks for the info
