I played around in Firecalc with 8% and 10% WR for 8 years then down to 2% WR for the balance of 30 or 40 yrs. Looks like it could work (based on past market history) with the 8% fixed WR, but the success rate drops to 50% at the 10% WR. Not surprisingly, the issue is that you can run out of 401K/IRA at fixed 10% burn rate. The system seems very sensitive in this range, so results may vary considerably depending on the software used and slight variation in parameters. Oh, I interpret the Firecalc output graphs (8% WR) as a approx. 40% PROBABILITY of having 50% OR LESS of original savings left by 70. So the risk is defined by both the % loss as well as the ODDS of loss.
I suggest keeping a sharp eye on your portfolio even with "only" an 8% burn. Recommend (somehow!) adjusting spending to maintain at least 30% of your original portfolio intact in all circumstances up to the critical 70 yr mark. Have you considered a Variable Withdrawal Rate for the first 8 years, perhaps set up to preserve 30-50% of your investments? This could work well for you since survival needs can be handled by pension & early(ier) SS, but the variable withdrawal can maximize the burn rate on good years.
As others have mentioned, it would be nice not to be 100% dependent on SS at 70. Having "dry powder" can help to deal with unknown risks like Low Term Health Care.
It looks like you have framed the two extremes, namely survival handled by pension & SS (early if needed) and "luxury" defined by a 8-10%+ WR from portfolio until 70. What would a nominal or middle of the road case look like, say a 4-6% WR until 70 look like? If you would still be happy with this, especially if facing a bad sequence of returns up front, then you would still have a nice fallback that allows significant travel and is still much nicer than just survival. Perhaps, only for example, you'll burn 4-5% in bad market years and burn 10%+ in great ones.
It's good that you have pension and SS enough for survival. I appreciate that you want to live it up while you are healthy and have the $$ to enjoy. We considered something similar, but much more conservative (4-5% initial burn, down to 3% in 5 years), but have been too cheap and lazy to do all the travel. Plus DW and I could never agree on where to go and what to do. Well, maybe next year. Until then, we're drinking better wine...
FB