Raise your overhead as slow as possible and only when needed. I my opinion one of the hardest parts of business is drafting a written business plan. I used to say "let it run you over before you decide to grow or shrink" but this means your victimized from the market rather than controlling what you will or wont do based on market and what one can offer.
I think if you're doing around $1 million+/- gross receipts annually you should have a good estimating program (that includes estimating software) and you should be able to handle the project management without purchasing expensive software or web based links. To accomplish this you will need great office filing habits and good PC skills I say this because project management is mainly about communication and tracking.
Communication to: estimate accurately, purchase, RFI, RFP, Potential Change Order (PCO), change orders, design, email & phone correspondence, man power, & job phasing.
Tracking to include: all the same items of communicating plus, billing, accounts receivable (pending receipt of billings), & close out.
Project management is integral to causing success and profit on any particular job. Jobs today have extremely fast deadlines and if its public works they demand extreme accuracy (these will be thoroughly scrutinized), for these reasons today an electrical contract must be managed electronically.
Most PC's have Microsoft Office Suite, which includes software that is correctly used for these needs. Office Suite usually includes: Outlook (email & calendar), Excel (spreadsheet), & Word (RFI, RFP, PCO, any written correspondence). As example most, if not all estimating, software can export to Excel spreadsheet; this is a good function for basic management to create phase plan, purchase, and track. Good office skills today require the use of a PC. Set up each project as a file folder using a template that includes other consistent folders inside. The goal is to limit scrolling to find information. Visualize a non-electronic file system these were file cabinets that were used "categorically or topically", file electronically the same.
Successful project management requires good
communication and connection to each project and to each projects
accounting. These are two distinctive items and each require accurate management, so a successful project manager will have a system that includes quick accurate access to each of these.
One of the companies I used to work for used
Accubids "ConstructJob Project Management Software" and I really like this, it's a great tool! Maybe Microsoft Office Suite or Project is right for your size and will get your business through the next 2-5 years, only you can decide this. But again grow according to your business plan!