Researching seems like 14 depth is more important than the 24" Are the 20" heads easy to find?That's because this is mostly a personal choice. If you know you'll be miking up most of the time, then you can go smaller if you want. If you have no problem transporting a bigger drum, then you can go bigger. I say if you don't know what you'll be playing or under what conditions, 22" is a great all-around size to be able to play anything. And besides, everywhere you go, there will be a bigger selection of 22" bass drum heads at any shop. If you decide to play some off-size, you may have to order heads, or get used to what's available of what little is out there. I play three sizes: 20", 22", or 26" and choose according to what I'm doing (or most likely how I feel), and I can use all three for anything I'm asked to play, so it's personal.
Depends on where you are. Here in Southern California, I'm used to being able to find what I need, and where I shop they usually have what I need in any size. This may not be the case in other states or areas. Depth is important on the transportation issue too. A 14" deep bass drum has been the standard depth for a long time , and now you can go out to 20" deep - but as you go deeper, the sound changes slightly, but the bigger hassle is how much stage space you take up, and how much space you need to get it in to the car. For instance, I have a 22x18 bass drum that I can't get into the back cab of my truck, but I have no problem getting my 26x14 in there. And a 14" depth puts me closer face-to-face with the other band members which is important in my situation, and I take up less stage real estate.Researching seems like 14 depth is more important than the 24" Are the 20" heads easy to find?