I see this input script:

4C is OP_PUSHDATA, saying next byte is # of bytes that go onto stack. Next byte is 14, which is decimal 20 bytes on stack... you say you want to push DATA1 (520 bytes) on stack?
520 bytes is hex 0x208, so maybe you want to say PUSHDATA 0x208 <520 bytes>?

And: "Data push larger than necessary" indicates a situation, where you use 2 opcodes, whereas a single one would be fully sufficient. Hence when pushing 20 bytes (hex 14) to stack, a single command "0x14" is sufficient (https://en.bitcoin.it/wiki/Script).

From another thread, I copied this comment into one of my scripts:
# 1.) OP_PUSHDATA1 and even OP_PUSHDATA2 are allowed inside P2SH scripts fine.
# However, there is another policy in Bitcoin Core to require that all pushes
# are minimal in standard transactions. That means you can only use
# OP_PUSHDATA1 when a direct push is not possible (up to 75 bytes), and only
# use OP_PUSHDATA2 when an OP_PUSHDATA1 is not possible (up to 255 bytes).