Tenn Tom Bridge Clearance - neither will probably work
First, your mast height is probably not either of those numbers as Hunter's specs take you to the top of the actual mast -not including the light, wind instruments, and antenna. My H356 has a 55'-3" spec "mast height", but is actually 58.69 feet to the tip of the vhf antenna and to clear the light and raymarine wind instrument it is 56.91 feet - that bends the vhf antenna which will likely snap against your wind instrument and will definitely take out your windex (mine was gone within 3 weeks of buying my boat in 03).
I've been down the Tenn-Tom (in a Cabo Rico 38 with the mast up) and there are flat bridges that are listed at 52 feet we cleared the vhf anteena by 2 inches. There are arch bridges that are listed as 52 feet and that is to the low steel at the side of the bridge. I have had mixed answers about whether it is clearance to the light (hangs down about a foot or more) or the structural steel.
You should measure both ACCURATELY by survey or by going up the mast and dropping a tape down. Most at KY Lake take the mast down and re-step in Mobile. It's not that big a deal to do that and I wouldn't buy my boat based on that as a limitation if I were you.
I have a spreadsheet that has all the mast clearances for all the bridges down the Tenn-Tom. You also need to adjust them each day for the actual water heights and there is a link on my spreadsheet that shows where to get the information and then you must manually enter it. If you want the spreadsheet, I will e-mail it to you if you post your e-mail. It worked for us in the Cabo Rico. You will need to also enter your own specific mast heights - including the lights, wind, etc.for it to work properly.
I have attached two pdf files - one is the listing of the bridges from the Tenn-Tom chart book. The other is the 356 mast from base to antenna, etc. - IT DOES NOT INCLUDE THE BASE TO WATER DIMENSION WHICH MUST BE ADDED!