When rebuilding my F2 with Wiseco 836 kit, I used only hose clamps and nothing else, and found it to be quite easy. brush the pistons with fresh motor oil, then put hose clamps on the pistons that are wide enough to cover your rings. Now tighten the clamps just enough so they are tight against the piston, but you can move them with your hand, with just a little resistance to moving. This will allow the clamps to slide down as you install them in the block, leaving the rings compressed by the block. Put 2 and 3 at TDC and slide your block over the studs, and with one hand, introduce the pistons to the bores. Now slide the block down, holding it as level as you can, until the clamps are past the rings and 1 and 4 are touching the block. At this point, you can release the block and use both hands to insert 1 and 4. continue sliding the block down until the rings on 1 and 4 are in the block, at this point the clamps on 2 and 3 should have dropped off those pistons. remove all clamps, and seat the block, and you are done.
The PO of the F had done the old frame mod for removing the upper end with the engine still in the frame, so i just put it in 1st to keep the crank from turning while doing this. When I replaced the base gasket on my K, I put a short piece of garden hose over the countershaft and gently clamped vice grips on it to rest against the block and prevent turning.
Hope this helps,
Gonzo