I have the BLS velodrome bag and I like it with some caveat and some possibilities to make it better.
It can carry everything that I need for s single day of racing except cold food and the expected bigger parts/tools/accessories like racing wheels, floor pump and rollers.
I can fit in the middle part: helmet, shoes, skinsuit, race number, a bottle of water, a second water bottle or a bottle of sunscreen, snacks, sunglasses and gloves.
The side part can take all the usual that a track tote would: 5x Chainrings, 5x cogs (which I instead use for more allen keys), a small torque wrench (even more necessary now with the TK FRD stem system), a full set of allen keys 2mm- 10mm, chainwhip and my 15mm box ratchet.
This setup makes it that the tools unbalance the bag and make it awkward to carry. This could be fixed by adding some chainring pockets to the other side (cause we always need more chainrings right ?). The switch to a backpack would be appreciated too.