Timely post as I am planning to do something similar using Device::Serialport::Arduino. I plan to process the message one character at a time probably using encode/decode. To allow variable length packets, add a data character count in the payload in case your data contains something that looks like an ETX and to help in detecting framing errors sooner rather than later.

I am I the only one old enough to remember SYNSYNSYNSTXDATAETXCRC as IBM Bi-Sync protocol from the 70's? In this context STX and ETX are ASCII character codes.

James