I have the Harlan Sharp 1.6:1 rockers on my Stealth heads. I have not had any problems with them. I am using the 5/16" smith brothers pushrods. I think 3/8" pushrods will require more clearance in the pushrod holes. I would even double check with the 5/16" pushrods as the higher ratio moves the pushrod/adjuster closer to the rocker shaft.
I don't think you will have any problems with the springs you have.
They coil bind at 1.18" or 0.725" valve lift if installed at 1.900".
Not sure your install height, but a bit less would add a bit more seat pressure (only 111 lbs @ 1.900".)
The retainer to valve guide clearance will be fine.
Not sure about Piston to valve clearance, but if the pistons have valve notches I'm pretty sure your good.