Hello Larry & welcome to the Lawn Mower Forum...
Your wanting to get out of bagging grass is understandable... Lots more work and less nutrition back on the ground with bagging.
Your deck may work ok just blocking off the discharge, a plug to keep the under deck shape, would be ideal but not absolutely necessary.
The multi blade configuration is OK but if you just stack 2 blades in an X pattern on each spindle you end up with the bottom blade lower than the deck was intended to have blades spinning... I tried that with my 44 inch Cub Cadet long ago and did not care for the results.
Measure your blade s and replace them with mulching blades you will have great results using them...
Even with the discharge chute open if you mow in a clock wise pattern, so you are discharging into uncut grass. You will re-cut it on your next pass and have no build up until you get to the center and then just re-cut that narrow strip a few times ... all the clippings will be gone. :smile:KennyV