Turbo Trainer Advice

Well yeah. We don't all want to be skinny cyclists.
Some have other interests in life.

It's wa just an observation, as weight going up hill makes a huge difference.

I remember playing rugby. Had to stop as I didn't have enough padding!

I could easily be 78kg instead of 86kg. I doubt I'd lose much, if any, power in my legs in the process.

86Kg = 225 watts to complete in 115 minutes.
78kg = 205 watts to complete in 115 minutes.

Its just physics.