Unless you have loads of space to create really gentle curves, curved platforms on models will always create too wide a gap and overhang issues - really no way round it.
But.....the platform on Low Ghyll is on a R4 curve although when viewed from a 'normal' angle, the gap is on the opposite side of the carriage and can't be seen. The platform nearest the viewer uses the platform fence as a view blocker for the gap.
It's one of the compromises I had to make and will probably have to do so again.
By putting the station across one end of the shed I think the main curve can be pushed to a radius of about 36" but I will need to tighten the approach curves to R4/R3.
Last time I cut the platforms from 18mm MDF but having seen how Barry put his together on Wykeham, I may try that approach - but I'm a long way from that as I'm still playing with templates.
As for finding the time, I find it's best to break down the jobs into small tasks and go into the shed with a clear plan of which part of the project is to be done next. It's a trick I learnt when I restored a car a few years ago - at no point did I say "I'm going out to build a car" rather "I'm off to put part X on." Do that a few times and before long the car was finished.