My solutions to RPGT waiver ; maybe bit dirty.....
1) Get bills to offset your profit. Bills like renovation, furniture, agent commission, or to create bills. (You know what I mean)
2) Undercounter. Declare lesser price in your new S&P, balance settled in cash. So you don't "seems" to be making so much.
3) Declare higher in your S&P if you buy a property now, for future benefit when you sell. (But you need to pay higher stamping duty)

These 3 methods shall be enough to offset most of your profit.