Maybe pertinent to the OP's situation, maybe not.
On my Mariner 19, the boat came with a fixed length topping lift running from the mast head to a clip through an eye on the boom cap. I wanted to be able to adjust the topping lift. So I mounted a cheek block at the mast head and ran the topping lift to the base of the mast. Don't like this arrangement either - topping lift gets in the way of the jib halyard, even tough they are on separate cleats. So I am changing back to the topping lift starting at the mast head but going though some type of eye/block on the end of the boom to a cleat somewhere amidships on the boom.
At anchor or dock, I use the topping lift and mainsheet and a line from boom to stern cleat to lock boom in place as a handhold or support for awning or boom tent. Generally I put the boom over to one side or the other unless using the boom tent.
just my experiences, yours will vary
Fred W
Stuart Mariner 19 #4133 Sweet P
Yeopim Creek, Albemarle Sound, NC