Which method for small batch..mash tun or BIAB?

I was thinking of making a partial (2.5 gallon) AG batch of the Dead Ringer IPA (two heart clone). The question is if I should use my normal all-grain equipment or do a BIAB.

My mash tun is a 48 qt coleman cooler with a manifold and I batch sparge. Can I do a 2.5 gallon batch in this or will the grain bed be too thin? I would prefer to use my mash tun but have questions about the size of it.

Last night I picked up a paint strainer bag for the BIAB method. I have only done the partial mash with extract with a BIAB type method and never done a full all grain but have read up on them. My normal kettle is 32 qts but I also have smaller 16 qt and a 20 qt pots. Problem is my chiller is sized for the 32qt pot and likely to big for the 20qt pot. Is it going to be to be a pain to keep constant hold temp with a 32 qt pot and a partial batch.

I plan to start making more smaller 2.5 to 3 gallon batches to experiment and get a variety of beers made and just wanted to know which way I should head.

Just do BIAB in your 20qt bot for ease of mash temp controls, and then sub an ice bath for your IC. Means buying ice, but with only 2.5gallons it should cool in a jiffy. In my experience 2.5-3 gal batches just don't leave me with enough beer. Unless you have the time to brew multiple times a month then 5 gallons is much more worth the effort. Then again, maybe I just drink too much.