Sorry for not answering sooner, but I’ve had hardly any time for tumblr lately.
From everything that I’ve ever seen or read it seems that Sid is perfectly happy about Garak/Bashir. While Andy may have started the ball rolling, they have both since run with it. Not that they were encouraged though. The following quote, from here, probably explains why there wasn’t more said on the subject over the years.
Paramount also ordered Deep Space Nine actors Alexander Siddig and Andrew Robinson (Dr. Bashir and Cardassian spy Garak, respectively) to stop engaging in ribald speculation about their characters’ true feelings for each other at fan conventions
If the convention they did together in Spain last year is anything to go by though, either Paramount has lightened up over the years, or Sid and Andy just don’t care anymore.
As for adding subtext, I have heard that they both played with that, and one of the writers has also admitted that he wrote Garak as attracted to Bashir.