I did have some info regarding this question but I'm sorry I have misplaced the reference and can only offer an opinion.

I cannot recall reading anywhere that the deck gratings created any landing problems, at all. They did however cause problems when 'smoking down' as you have pointed out, switching from the deck grate exhausts to the side ducts for launch and recovery. The after part of the ship was quite uninhabitable with fumes and smoke always hanging low about the stern until dispersed.

I believe and this is a bit of a long bow but I can't find any evidence to the contrary, that the ducts caused no landing problems because not only were they sighted about thirty feet each side of the deck centre line, but also the leading edges were one hundred and twenty feet behind or aft of the first of Furious's four arrestor wires. Even though they were an obvious hazard, all of Furious's aircrew over the years managed not to undershoot even during the 1920's when there were no lateral arrestor wires and if this is the case hat's off to the skill of the RAF trained (until about 1937) pilots. The grates did not interfere with deck parking because the Royal Navy rarely practiced it, almost always stowing a/c in the hangar.

Before the lateral arrestor wires were settled upon though the RN did lose several a/c over the sides amidships which resulted in the installation of the deck pallisades in 1927 but these were removed after 1936.