16' is the minimum size allowed. Depending on the amount of $ you want to spend, you need to decide what type of material you want your boat to be made of. Aluminum is lighter than fiberglass, less expensive & repairs usually are stronger than those made with glass. An aluminum can take more wear & tear than a glass boat, I wouldn't want to beach a glass boat at the ramp at Starved Rock, a keel sheild would lessen the amount of wear by a lot. Glass boats in some opinions look nicer, more curves, & ride in rougher water better.
Do you want a tiller or a console? I prefer tillers, much better boat control, downside, larger motors are not advisable unless you get hydraulic steering. The tiller allows the boat to be completely open from stern to bow, no console in the way, downside- in a heavy chop I need to wear my Gortex, a lot of the spray comes over the gunnels.
I'm looking to upgrade to a 19'lund with a 100 h.p. 4-stroke tiller. Walleyesinc & walleyecentral both have used boat postings on their sites. Good luck, Chad
Watched Cabela's Outdoors yesterday and saw a Guide from Washington with a very big Alumaweld boat and it had a Merc. 250 Tiller on it. I was amazed they even had that option available. I can't imagine handling that kind of power with a tiller.