What size of tires should I use?

Please give me some suggestion for the tires size.

I have the front 19X8.5 +36 and rear 19X9.5 offset +44.

The front I mount with 235/35/19 without any problem.

The tire shop owner told me the same size of tires cannot be fit on 19X9.5.

What size of tires should I get for my rear wheels? 

I would like to put the wheels on my Estima(Previa).

Thanks in advance!

Alan
[email]rracing@hotmail.com[/email]

215/35/19 in front.. and 225/35/19 rear...