Slime tube sealant, has anyone tried tube sealant on small inner tubes?

A dose of Stans in an inner tube weighs about 20g. IME, a tougher tyre will have a much greater weight penalty. I can't say I've ever noticed any wheel imbalance as a result of using Stans either in inner tubes or tubeless set-ups.

^ This. I never got the "additional weight" thing. I had no idea how much the sealant would weigh but I was pretty damn sure it'd be less than 50g, much less than the additional weight of an extra tough tyre.

Like I said above, the two bikes i'll be using it on are close to 25kg, I won't notice the weight at all. Then there's the fact that it's hard to find 700-37 tyres with puncture protection that don't look utterly daft on an old Dutch bike. I'll be going with the usual £7 ones that usually last 2 years or so with a dollop of sealant and i'm sure that'll work quite nicely!