It's generally preferable for me to receive models already assembled and cleaned of mold lines, but in cases where this is not possible assembly and cleaning time will be charged based on my hourly rate.
At least where Games Workshop products are concerned, it can take up to 90 minutes to build and clean a 10-man unit, and 60-90 minutes to assemble most vehicles. Tweaking poses or any projects that involve pinning metal parts can add additional assembly time. Drilling weapon barrels is considered part of the cleaning service.
When it comes to the painting stage, I aim to spend between 45-60 minutes per infantry model, with vehicles taking around 2-2½ hours to complete. This gives a very effective tabletop finish for the time spent, but there is certainly room to add additional detail and effects to miniatures if you'd like some extra time spent.
All armies will be based in the style of your choice unless requested otherwise, and if you wish to consider pre-cast basing options, Secret Weapon Miniatures do a variety of highly detailed resin basing kits that may suit your tastes. Please note that I am in no way affiliated with Secret Weapon. Justin is just a really cool guy, and creates some very fine modelling accessories!
Once an army or unit is finished, it will then be varnished with two coats of gloss varnish, for durability and to protect the paintwork, and then a final coat of matt varnish to take the unsightly shine away. For organic armies (like Tyranids) it may be preferable to have them remain glossy, in which case I can simply end the process after the 2nd coat of gloss is applied if you would prefer.
Army projects can either be processed all at once, resulting in a lump sum payment at the end of the project (typically a week or two after work starts, depending on the size and quantity of miniatures), or can be broken down into a unit or two at a time and completed over a longer period. Whether you need an army by a deadline, or you'd prefer something taking shape over a few months, just let me know and I'll be more than happy to come to a mutually agreeable arrangement!