Also enabling them to rollover IRAs and old 401ks into a Solo401k.

Two huge points you are not mentioning: the up-to-$50k loan that can be taken from the SD401k for any purpose, and the fact that the SDIRA requires an LLC to enable checkbook control (which is the only way I'd invest due to convenience, speed, and lower custodial costs), whereas the SD401k does not need an LLC.

It would supplement my income, cover gap funding & put our business on the map.

This will enable you to know what you'll make (% wise) so you will be more consistent.  

Willing to supplement a lack of real estate experience with hard work and and eagerness to excel. 

If you zoom in with this enabled, you'll get the tax parcel number for any property.

It also allows you to set multiple passwords that enable different cameras - so everybody can see the parking lot and laundry room, but maybe some areas are more restricted (IE, a tenant can see their own entrance only).

It is supplemented with Umbrela insurance.

My ultimate goal is to build a strong portfolio that will produce enough positive cash flow to supplement my current income in the short term and eventually enable me to quit my 9-5 and focus on investment full time. 

I believe that margin is really the important part, so taking that tax shield into your calculations gives you absolute clarity that could enable you to offer just a smidge more to close a deal.That's my theory anyway...