I do not have any experience with an account or using a SD-IRA account but I have done a bit of learning about it. 

Account Closed,One approach you might explore is to build up value in your 401(k) including your employer contribution, roll the vested value into a SD-401(k) or IRA, and then go from there.David J Dachtera"Success is not a destination.

For asset protection reasons, you might want to separate the asset holding entities (passive side & pass-through from taxation POV) from the public facing operations/property management shell entity (the active side & which can be taxed as S-corp if you want to create self-income for other purposes, like being able to establish Solo 401K and roll over other 401K and IRA funds for further investment options). 

Financial Planning would encompass the entire portfolio of any individual (especially including external concerns: 529 Plans, Retirement planning, Roth IRA's, annuities, and the list goes on).

What about combining it with IRA & 401k contributions.

I have some rentals I manage myself and one rental in a self directed IRA.

They do Self Directed IRAs and a lot people are looking to invest in real estate using their IRAs.  

They wouldn’t discourage you from investing in a 401k or a IRA.  

I know many that sweep their accounts when business is up and put it into multiple buckets while they can.Buckets like:- IRA accounts- Insurance Contracts- Family Trusts/Partnerships- Self-directed 401K’s- Health Savings AccountsAnd you don't necessarily need to own these buckets, sometimes control is better and safer than actual ownership.

I then rolled an old 401(k) into a self directed IRA and began to invest in my IRA.