More info would help.
Is it a cabin-top traveller? if so and you need a
winch, it may be better to add parts to the mainsheet to make it easier to use. This will require some blocks and a longer mainsheet.
It it's feasible to move the traveller/mainsheet into the cockpit area, then it would be more at hand while sailing. Again, it sounds like you need to increase the purchase to make it manageable though moving the mainsheet attachment aft on the boom immediately gives you better mechanical advantage and you may not need the extra tackle.
If it's already in the cockpit area, then you might consider changing to a bottom block with cleating after you increase the power of the system. Also a ratchet feature on the bottom block will help manageability when the wind is up and when you are gybing in a breeze.
it may also be possible to add a "fine tune" section, that pulls on the "fixed" end of the sheet with another multipart tackle. This multiplies the power greatly, but doesn't give you a lot of adjustment/foot of takeup. However it allows further sheeting at heavier loads without a
winch.
Good luck - try to set it up so that a
winch is not required - much faster and more effective to use that way.