@Richard Unsworth If you anticipate that your income will significantly increase as well as your tax rate next year, it would be in your best interest to wait to do the studies. On the other hand, you could do one or both properties this year and roll forward any unused tax benefits each year until exhausted. Another consideration for you is that if the cost seg study is not done in the year of purchase, it will cost you more in following years because you will need a 3115 Change in Accounting Form done to change from straight-line depreciation to accelerated depreciation.
BTW, be aware that a cost seg study and bonuses are based on the year of purchase and occupancy as a rental, not the date of doing the study. Therefore, if you purchased with occupancy a rental property anytime from Sept. 2017 to Dec. 31, 2022 and did the study later, you would still qualify for 100% depreciation when filing your taxes. There were bonuses available prior to the 100% bonus and there are bonuses available on properties purchased after 2022 as well...just not 100%.