Several things at play to have the genoa tack easy. Its how you release, the size of the line , size and type of the blocks, how you steer, how you pull it in, and the shroud protectors or rollers.
Most of the time you need to release at the instant the jib backs against the shrouds. Sometimes you hold it a fraction of a second to help turn the bow for a faster turn. Hold your thumb up and watch the jib, release in one upward pull , pulling all wraps off winch at once, look down and watch for tangles in the sheet and free them if needed, let the sheet run.
Line size makes a difference, 5/16 works good, 3/8 is about max, unless you have large blocks
Blocks do matter, ball bearing is better, larger is better. line size must be compatible with blocks, small blocks need small line
Steering and trimming in go hand in hand, enough said.
When pulling in, pull very fast to take slack out, but leave just enough slack so that the genoa gets blown past the shroud on its own . If you pull the genoa all the way to the shroud before it blows past on its own, it will bind up. So pull almost to the shroud, when it blows past , instantly pull the rest of the slack out of the sheet before it fills. speed is your friend, the better you time it and the faster you do it, the less you will have to winch in. . It helps if the skipper steers correctly. Sometimes delaying the bear away a bit to give the trimmer time to sheet in. But the trimmer needs to be fast or the boat will be slowed way down.
In my experience having a pvc tube on the front shroud about 3 foot tall really helps. The tubes on the middle and aft shroud are just windage , and don't help much. You are better off with a tall tube on the forward shroud and none on middle and aft, than if you have a short tube on all three.
When I switched from the 1 inch non ball bearing blocks to Harken 2 1/4 inch ball bearing blocks I noticed an improvement, My line is 5/16 dia. So if you are doing everything else right get bigger blocks as the last step. 3 inch blocks are a bit over kill, but depends on line size
I agree with the previous comment. I see no reason why larger blocks would help here. You need to allow the wind to take the genoa to the other side of the boat before you sheet it in.
Some people also install plastic covers on the front shroud to help prevent the sheets from hanging up. One member of our fleet, Fleet 72, has installed covers are free to turn on the shrouds, though that does add a bit of wind resistance.
See the item “Forward Lower Shroud Roller” in the section titled “Nifty Ensign Ideas” at https://sailsaratoga.org/ensign.
When I tack or gybe my genoa often snags on one of the shrouds. A friend said the reason is that my two jib sheet blocks are too small. He recommended getting a pair of Harken 3" (76mm) blocks. Would getting bigger blocks really help, and if so what size/type do I need?