Sealing ported enclosure to reduce boom

Hey Ifsixwasnin9, put a sock in it.
Seriously, I owned a pair of Acoustic Energy speakers that came with port plugs. The speakers had more bass than was needed in my small room. With the plugs inserted the bass was much tighter and tuneful. Give it a try.
Nice screen name BTW.

I agree with stuffing the ports too. You may want to position them differently (more or less toe-in - closer or farther from front or side walls - etc).
If what you are asking about adding 'fill' as in adding sand or shot to them that will tighten the sound from top to bottom. Try one thing at a time. Adding 'fill' may also make them forward sounding .
That's my opinion and good luck

Partially blocking ports is a valid option. You have to try it and see.

Yes, I have in fact even used socks on occasion to do it.