I think most of the bases have been covered, e. g. double boxing, must have all original packing materials etc. Don't think the mail system is worth the risk. Also, increase the insurance value to the $5,000 level, not to scam the system but to get in the special handling track that both carriers have for 'value' shipments. While that will cost about $25, it is worth the extra cost if you have a high value items. If a claims does result you will only get paid what you can document as the value. Finally, do not ship turntables, they are a pick up only item.