Ratchet Block Quandry

[seawolf]

Hello All,
In Brion's DVD Going Aloft, he is using a Harken Ratchet block to hoist up first with a line reeved through it to be the chair hoist.
It looks to be a 3 inch block from the DVD, with a slider control on the side to activate the ratchet. I have been unable to find this type of Harken ratchet block in 3inch.
Not in the Harken catalog.
The 3 inch I found is a Hexaratchet and it has the small dial type control on the side. I do not like this as you need to pull the tension off the block before being able to switch over to free running.
I found the Harken 2inch ratchet with the slider control but it doesn't seem to have the same holding grip for the 3/8 inch line I am using.

Another point, I would like to switch to a larger line (1/2) that is easier on the hands also.
Any ideas?
Thanks.
Seawolf.