Regarding "your age in bonds", it's worth noting that Vanguard's all-in-one retirement funds don't follow this advice at all. For example, the Target Retirement 2050 fund has 10% bonds [1], while I would expect most people buying this fund to be 30+.
I'd suggest ramping up bonds shortly before retirement (and then ramping them back down again afterwards, which the vanguard funds do not do -- mostly because they cannot tell if you have actually retired on your target date).[1]
[1] https://investor.vanguard.com/mutual-funds/profile/VFIFX