I would vote for paying the pros as well.
I've had recent experience with the FlexHone on an aluminum block engine, with wet aluminum liners, and it left tracks on the top flanges of the liners, which I wasn't expecting, or at all pleased with.
Brush Research are very clear about keeping the FlexHone rotating while inserting & extracting it from the cylinder bores, so on insertion, the balls will tend to beat up the deck of the block. So if you opt to go this way, make sure you have an old head gasket in place to protect the top deck. YMMV since you have an iron block 2UZ.
I would also recommend you "break in" a new FlexHone on a piece of similar sized pipe, as the balls of a brand new FlexHone tend to "shed" some of their abrasive. This shedding will dissipate after 20-30 strokes.
Lastly, in several of the YouTube demonstration videos, only an initial application of lubricating oil is shown for each cylinder honing, however I don't believe this initial coating is sufficient. Brush don't address this point in great detail, but do recommend that you keep the bores/hone well lubricated.
If you have the option, I'd put the block over a tank, and have a continuous flow of filtered, clean lubricating oil in each cylinder during the honing process, then clean the FlexHone after each cylinder.