Hi Ray, Thank you for your question.To get to the diverter on your model P299508LF faucet you have to unscrew the cap on top of the spout, and remove the plug and o-ring to gain access to the diverter. There are slots on top of the diverter where you can use a coin to unscrew it from the spout body. I have attached a link to the owners manual for your faucet below which includes the parts breakdown that should help with your repair. Thanks, Dave http://www.peerlessfaucet.com/customer-support/find-repair-parts/documentation/p299508lf.html?document=mi&documentIndex=0

Hi K, Thank you for your question. The base plate on the model P299508LF measures approximately 10-1/16" L x 2-1/2" W. Thanks, Dave