Change of seat style & Bars

I have a few questions any help greatly appreciated: Do I need a different seat base if I want to put a lower profile seat (flat tracker sort of style) on my 1980 XS400 Special II ?
I'm also after a fuel tank preferably Blue if anyone knows of one?
Will putting regular lower flat track style bars in require the cables to be shortened?
also what's the widest tyres that would possible fit? any help appreciated... Thanks.

If you want a tracker style seat you'll probably need to chop off the back right before where the stays mount and then fabricate some sort of loop that's shorter for the taillight and plate to mount onto. Not sure if anyone makes specific seats for this but there's lots of people that have converted to cafe or scrambler which have similar seats.

If you have free time due to quarantine you can always make your own base out of fibreglass. I know people on this forum always just say "buy stock" but there are things you can diy sometimes.

Do you have a stock tank? just paint it yourself. not too hard if you take your time . If you don't have one i have a spare red stock one i can sell but i doubt you want to ship from canada.

You'll just have slack in them in shouldn't be too much shorter.

Not sure on the tires. Probably in one of the manuals shouldn't be too hard to find.

Thanks for your reply. I may just keep it all original then. I have the tank but its got a few dents one of which is heavy so I guess I will try and get a repair job done...

Maybe message Drewpy. He lives in the UK so he knows local suppliers, plus he built a flat tracker.