Ok I have a hard time finding 700 x 35 tubes, can I use a 26 or 27 " schrader valve tube ??

26" will not really work. It might be possible to stretch one into a 700c tire if you were desparate, but you shouldn't if you have any other option.

27 X 1-1/4" however, is almost identical to 700 X 32, which is just a couple mm narrower than 700 X 35. So a 27 X 1-1/4" tube will work.

WHere are you looking for tubes that does not have 700 X 35 or 700 X 32/38? Even Walmart and Canadian tire have them where I live.

A 27" X 1 1/4 Schrader tube will fit perfectly. That's a common size so it should be easy to find.

Ironically, 700 X 35 is a far more common size on modern bikes, but I guess some retailers didn't get the memo.

Assuming you have rims drilled for Schraeder valves. I would have guessed that most 700c bikes would have Presta valve drilled rims?

In case you aren't aware of the difference, Schraeder is wider, so requires a bigger hole. It's also usually only found on low end bikes, and more on mountain bikes than road bikes (but still only at the low end/department store type models).

I think many hybrids and city bikes, with the exception of higher quality 'performance' models, have schrader.

I used a 26" tube on a 700 x 32 on a touring tire.
this was a few thousands km ago. I almost forgot about it.
and I use it at 80-100PSI, too.

I don't doubt it would work. I just think it would be more difficult to mount. 27" tubes (and their cousins - 700C tubes ) are almost as common as 26" tubes, so the former is the better choice if available.

I think so too. Actually, I'd be surprised if the box didn't have both sizes marked on it. Bikes with 27 X 1 1/4 tires haven't been made for about 25 years but we still get tons of posts asking about them.