I often play the Toucan system which uses transfers over 1C openers, 1D is either 4 diamonds with a singleton or 6+ D. Majors are standard 2/1 and 1NT is 15-17. Originally, we pre-alerted, but now we just alert/explain the bid, not the ramifications. The system is legal and was named by Matt Smith, National ACBL Head Director. For those who want to improve their game, I recommend Toucan. I found it helped me "see" the distribution far better and it right sided the contract. Duplicate Bridge is made up of mostly seniors, people set in their ways and usually not friendly towards persons who play something different from themselves. Since we switched from pre-alerts to alerting just the bid as a transfer to the suit we identify, we have found we no longer get complaints. The opponents "see" the transfer or relay as some people call them, just like transfers over NT openers. Transfers are legal and right siding the contract is worth a half a trick. So try alerting only the bid, not the system. Good Luck.