Sounds like you have the R4 tires on it the other tire size you mentioned are the R1 tires they are on different rims so the size is different to keep the ratio good between the front and rear.
Those extendable links are only made to do so to make it easier to hook up attachments after it's hooked up you should lock those back into their closed position they are not design to stay extended during the use of your 3pt attachments.
Installed another kit on a Woods SB84C today here kits are awesome sells them on Ebay too I'll post a link below. If you want a universal chute deflector these are hard to beat.
See his stuff here