These photos are from my 1928 Iver catalog. Your bike looks like the 87M. This bike normally came with Vitalic Cord 1 1/2". Optional tires were Vitalic Cord 1 3/8" or 1 5/8". Fisk Non-skid or US (Indianapolis) Chain Tread, double clincher tires 1 3/8, 1 1/2 or 1 5/8" tires. It looks like you have the clincher rims. I think that modern 700c clincher tires will fit. Your saddle looks like the saddle that came on the these bikes which is a Persons #2 padded saddle.