Don't believe the prevailing wisdom "don't touch your retirement money to invest in real estate." that you are being told. Do whats right for your goals, needs, and experience. A stock broker with never tell us to withdraw funds from our account to buy real estate haha. Joking aside, using a SD IRA for real estate can be a great tool if done correctly. You will find lots of threads on BP for more research and references for sure. Here are a few tidbits that I learned from my experience;
1. If I would do it again, I would probably lean towards the "checkbook control" option that you are referencing. I have one without, so I have to instruct the custodian every time a payment needs to be made. Although not necessary in my case (not flipping or making lots of transactions with it), it would be helpful/more convenient. If flipping, I would consider it a must.
2. The custodian matters. Find a safe one that you trust, has fees are reasonable (will be much higher than your standard brokerage account), and has great support-you will need it. If you can find one that has a physical office near you, that would be a nice bonus.
3. Be very careful that you follow the IRS rules. In a lot of cases you will naturally walk a fine line with the rules, especially with the checkbook control. The hardest one for me is the concept of not adding value to your deals (other than basic management). If you were to simply do a repair or something like that, the government could theoretically impose a distribution of your retirement account and then you would have to pay the tax and possible penalties.
4. Know the "Why". And know that tax pros and cons for a SD IRA for your particular strategy.
Sounds like you are on the right path with your research.