You can go to the 140/90-15 - it is a bit tall and some folks like that it raises the gearing and the extra bulk helps stabilize the bike in a straight line.  It generally doesn't have any rubbing issues - the bolts holding the chrome rails on the side of the fender have very high heads and you may need to replace those with bolts having a shallower head.

Some folks have put 150/80-15 on the rear - it can rub badly and really is too wide of a tire for the rim.....it squeezes the beads in and makes the tread profile too round.  It will slow the bike down as they are far heavier than the 140/80-15 or 130/90-15 - which are the best size tire for the bike if you want good handling and acceleration.

There are white walls that can be added to your tires - they are commonly called "Portawalls".
https://www.google.com/search?q=portawalls+for+motorcycle+tires&client=firefo...

Maybe you should look around a bit.

https://www.ebay.com/itm/186026526325?_skw=motorcycle+portawall&itmmeta=01JWF...