Keep to as near to the original as possible. I think you should be able to find a replacement on ebay. You need the size of the platform the pinion and teeth count plus the length of the escape wheel. You don’t want the escape wheel bracket to interfere with the rest of the movement. If you cannot find a cylinder, you should be able to get a lever escapement, the above info still applies.
A lever plateform will keep better time then a cylinder. A cylinder is not compensated.