Why would you want a HUGE knot 150-200 yards back in your spool?
You would be far better off to remove the 80lb. mono, (Some shops are able to remove line onto another plastic line spool for you.), and refill the reels with 130lb. hollow spectra. Figure about 600 yards per reel. This will leave plenty of roon for a long topshot of whatever size or color line you wish to fish. Once you learn how to do the connections you will be able to make your own topshots very cheaply and you will save money in the long run by not needing to buy as much mono as often!
The initial cost of the spectra shouldn't be a problem for a guy that can afford a 24' Boston Whaler.
FISH HARD!
Chris