I need advice/opinions on snug vs loose fit tubs in rack

I made this two shelf rack and used a piece of 1/8" pegboard as a spacer (because I thought that was a pretty common way to get the right fit). Now I'm noticing that most racks (both DIY and purchased) have a very snug fit. so far I haven't put any holes in the tub because of the even 1/8" gap all around the top edge. On the first day, i tossed a probe in and was happy with 67% humidity but the tubs must have still been slightly damp from cleaning them out because they are essentially my room humidity of 50-55%. I'm seriously considering dropping the shelves to make a snug fit and I'm just wondering what the pros/cons are. It's a closed rack (because of fluctuating room temps) made of 3/4" melamine using sterilite tubs (either 2 15's or 1 32qt per shelf). Any advice/info would be appreciated. Also, anyone with the RBI or Boaphile closed racks: are there any openings on the back panel? I noticed the RBI has some slots on the sides, are they for ventilation? The Boaphile looks like it has no openings at all, is this correct?
I know if I drop the shelves for a snug fit I will be putting holes in the tubs, would it be recommended to have holes even if I keep them as is?

Notice the placement of the holes in my tubs, it provides better airflow, and keeps my humidity down. Keep in mind along with humidity, you want proper airflow in your tubs

http://i165.photobucket.com/albums/u...ishrack3-1.jpg

[QUOTE=llovelace;1634629]Notice the placement of the holes in my tubs, it provides better airflow, and keeps my humidity down. Keep in mind along with humidity, you want proper airflow in your tubs[QUOTE=llovelace;1634629]

Do those holes continue all the way around on all four sides or just on the front and back? Also would you recommend this type of ventilation for any tub, even if it did not have a snug fit at the top?

When I first went to a rack system, the first tubs had them on all sides, now I do the front & back, and the center of the sides. My tubs are very snug fitting, that's why I put upper & lower holes. You may only have to add them to the lower section of your tubs, since yours are tight fitting

*aren't tight fitting

ok, thanks. what about the cabinet itself? should it have some holes drilled in the back panel or will the convective current of the low and high openings on the tubs be sufficient? I do want to keep the heat in the area (esp. during winter) so I'd prefer not to put a lot of holes in the back panel. . .

I have back heat, so there are no openenings in the back of mine.

Well I've put the holes in the tubs, couple of rows along the bottom on the front and back. I think I'm going to modify the shelf height later tonite to obtain a snug fit, I'll have to add holes along the top too. Has anyone had any homemade racks with loose fitting tubs and if so did you modify it to make it snug or did you make it work with gap at the top?