To answer you question, no that is not the best way.
The best way would be to place the antenna where it needs to be and then set the antenna.
(though im sure you are aware of that lol)
The reasons for that is:.
A antenna at different heigth from the ground will (sometimes sligthly) have a difference impedance. Therefor the SWR will change.
For example a horizontal dipole almost on the ground will have a impedance of almost 0 Ohms, but up in the air in can be as much as close to 100 ohms. Those excesses are present below 0,5wl in heigth. Beyond that heigth the impedance will vary between 60..80 Ohms.
As W5LZ says it is for practical reason (well said), you can try the described methode.
IT is the recommended menthode. In most cases will produce the best stetting.
It worries me that your SWR is far off by using this methode.
In case of a horizontal antenna and if i interpertate your reading "sky high" correct?
If the antenna is "free" of obstacles (beside the earth in the back ground) you should be able to get a lower SWR reading. In that case, please verify if nothing else is wrong.
@ Homer BB,
The one wich suggested to you the two elements quad can be 50 ohms is rigth (But!)_
There is a very very big BUT, there will be a heavy sacrifice in almost all other aspects (Gain/FB/bandwidth etc) in such a way i wouldnt recommend it to anyone.
not aware of a 2el Quad wich still has a good performance and is 50 ohms.
Your decision to use a 2el Quad for vertical work is probarbly the best.
Not only did the mast have a negative influence on that tuning proces for that yagi, but keep in mind that also goes for the rest of the values of the antenna.
Where SWR is something you can adjust, that doesnt goes for FB/Gain etc...
I still am
a bit puzzeld why most manufacturers claim that the yagi can be set vertical.
As it often has a very negative influence on gain/fb etc.
Henry 11 meter Dx antenna systemx