$iShares barclays 20+ Yr Treasury Bd(TLT.US)$Tesla(TSLA.US)

Often, we overcomplicate simple issues.

At this point, buying US bonds only requires considering:

First, can my annualized return on US stocks stably exceed 5% under low-risk allocation—corresponding to long-term bond rates?

Second, will I hold USD-denominated assets long-term—corresponding to USD depreciation risks?

So my understanding is simple and will be consistently executed:

Here, the question isn't whether to buy, but how much to buy.

For each price point, what should be the proportion of my US bond holdings, and then reverse-calculate the purchase amount for each point.