Which Tyres?

Latex 19-23 size tube in a 28c tyre, any predictions?

Depends upon the design, manufacture etc. On our touring bicycles-- where clinchers instead of tubulars get mounted-- I use Pariba Latex 19/23 with 25mm and 26mm tyres. These are handmade inner-tubes and quite variable. Some thinner, some thicker-- the thinner still a much heavier guage than what I've fished out of tubulars.. I'd have no quarms using these with 28mm Continental 4 Seasons..