Torah Service U - MB

The custom is to cover it [the Torah] -

And it is not appropriate to use just any cover; the Taz (David HaLevi Segal) wrote that despite this minhag, we don't need to cover it in general [between aliyot]. Covering [the Torah] is too much of a pain, and you only need to at the time when they say Kaddish after the leyning. It's appropriate to cover it then since there is a pause between the readings. The rule is that any situation in which there is a long time [between aliyot], like when they call up a chatan [i.e. when they sing to call a b-mitzvah up for an aliyah] or there is a lengthy mi shebeirkah, then we cover [the Torah] in the way they suggest.

Our custom is to have a middleman -

It is our custom that the gabbai or the one who purchased the mitzvah [i.e. made a donation to the shul for this honor] stands next to the Torah - this person is called the "sgan" [assistant] - such that there will be three people [standing by the Torah]. The sgan is, metaphorically of course, in place of the Holy Blessed One - since they are present for all who desire it [the Torah]; the reader is the middleman in the place of Moshe; and the oleh [person having the aliyah] is the receiver [of Torah] in the place of all Israel as their shaliach [agent]. And in truth, this is an early minhag that three people would stand before the Sefef Torah, as it is written in the 14th chapter, 14th halakha of Masekhet Sofrim. [And it's brought in the Or Zarua: Hilkhot Shabbat halakhic work of the Riaz] However, there it suggests a different reason: "It is inappropriate for the leader to stand alone before the ark, rather someone should stand on their right and on their left, analagous to the Avot [Avraham, Yitzhak, Yaakov = 3]