Tyres sizes

[Jacks the Lad]

My recently acquired 350 Scrambler came fitted with 350 front and 410 rear tyres. They look too much for the rims and the handling is horrible. So far all I have spoken to agree they're not right but can't agree what size they should be, I have seen quoted 275 front and 300 rear which seem a bit too much the other way, Can someone tell me the ones that are correct?
Thank you.

[graeme]

For what it’s worth I use Dunlop Roadmasyer TT100 GP
Rear 4.00 - 18
Front 3.60 - H19
Handles and tracks very well

Graeme

[graeme]

I forgot to say 450 last model Scrambler