Different bracha on techeilet?

Rav Kook Zt"l in his chiddushim on Shulchan Aruch sites a difference of opinion in the Achronim regarding what is the correct bracha on donning tzitzit. On opinion holds the correct nusach is בְציצית with a sh'va while another holds that the correct nusach is בַציצית with a patach.

Rav Kook suggests that perhaps the nusach is actually dependant on whether we have techeilet or not. the nusach with a patach implies the Hei HaYedia which means THE specific tzitzit that was commanded in the Torah. The sh'va nusach is when there is no techeilet and we are still commanded to put tzitzit on the four cornered garments we were even though it is not the full command of tzitzit in all of its details.