Nino, some very honest feedback.

I never used RTBB in the past because it did not offer credit card or PayPal.
Any business in 2015 must be modernised or you will lose business hand over foot.

Secondly, after running my own business for the past 25 years and turning over millions of dollars per annum in the good years, my advice is that you MUST hire staff and grow for both RTBB and your Aust Pinball Restoration business because being a one man band in any business is a recipe for disaster in both efficiency and profit as well as gross turnover. Letting go and getting in help, contractor paid or salary will be an instant smart decision the moment you do it. Then u will say it was the best decision or decisions you ever made.

Start by getting a contractor in a few days a week then move to full time employment.
Delegating and teaming up is the most successful way to keep a business alive and growing.

I can only speak from 25 years of running my own businesses in highly competitive environments and being profitable and at the top of the game cause I took advice from people who had more experience than me in the early years.

I hope to see your two businesses succeed.
I never had a backlog and I never turned away a customer from day one cause I took the plunge and trusted others to work with and for me.

Staff will fix all your issues.
If I didn't think my advice wasn't helpful to anyone starting out in business I wouldn't be sincerely offering what I feel is honest advice or feedback. Hope it helps.
For the record, I am proud of what you have already achieved with APR and RTBB. Well done mate.