Hi,
That could have been one of my posts you read about the B77 alignment. I use 468 tape (previously Agfa, then BASF, then EMTEC and now RMGI) and set a reference level of 355nW/m on the B77 Mk.II, which is 3dB higher than the 250 recommended by Revox. I also set my meters to read 0dB at reference level, whereas Revox recommend a "ballistic lead" of 7 dB if I recall correctly. So my setup is a total of 10dB "hotter" than the recommended Revox setup.
I reckon that about half of that 10dB difference is accounted for by the difference between 468 and the typical 1970's consumer tape, and the other half by the use I put the machine to. I record mostly chamber music and small acoustic ensembles without percussion, so there's not a lot of high frequency or transient energy there to cause overload problems and I can run the tape hotter to get lower noise.
Whatever blank tape and whatever reference level you choose at whatever tape speed, you can quickly see if you can make a bias adjustment at that level on that tape at that speed. Record 1kHz at your reference level, and set the bias for maximum output off tape. Then switch to 10kHz at the same recording level and set the bias for maximum output off tape, before increasing bias to reduce the output level off tape to the prescribed 10kHz drop-off. If you can't find a 10kHz maximum that is fairly close to the 1kHz maximum, then the tape is saturating and you need to use a lower level for the bias adjustments. You can double check this once the HF record equalisation has been set, after setting the bias. Tweaking the bias for a maximum again, after setting the HF EQ, should give a maximum at 10kHz which is higher than the maximum at 1kHz, dialling in the prescribed overbias will restore flat response.
Using 468 in the B77 at 15ips and at 7 1/2ips, I could get a 10kHz maximum close to the 1kHz maximum at my reference level which is 10dB higher than Revox' recommendation. I wouldn't think you'd choose a higher reference level than that, so I would think you should be OK to carry out your bias alignment at any reference level you choose. And if you're in any doubt as to the dynamic capabilities of an A77 with 468 tape, find a copy of the the famous audiophile favourite recording "La Spagna, Siglos XV - XVI - XVII" on the BIS label, made in 1979 or thereabouts - I think the CD is still available. BIS used an A77 at 15ips with 468 tape to capture that, and anyone who's heard it can vouch for the dynamics and the frequency range.
Good luck and best regards,