I have a 12' semi-v on a trailer I converted from the trailer of a 16' ski boat, I love the long tounge on my setup, even had plenty of room to mount a 1 1/2'x3' cargo box on it for my PFD's, jack, and other emergency equipment.
Looks nice; the tongue on the trailer for my 14' Valco is so short (used to be a tilt trailer) that I can't lower the tailgate when it is hitched up and I have to put a bit of my full size truck in the water to get it off on most launch ramps.
On the flipside it fits the garage nicely, I'm thinking about fabbing up a removable extension piece for it.
I'm in the process of refurbishing the trailer for my 14' ClackaCraft drift boat. The previous owner towed it with a "78 Chevy crew cab pu. So He had lengthened the tongue a foot with a somewhat crude (but hell for stout) splice. But I tow it with an "84 Toyota 4wd standard cab. It was nice to trailer and to back down a ramp but a bit unwieldy to back into tight spaces like my driveway. So I elected to cut the extra foot out and cleanup the splice area. I hope I didn't shoot myself in the foot! I'm having major second thoughts. It sure was nice backing down a ramp.
Being in an area where most launches are salt water, I like to have at least 3' ahead of the tip of the bow on all my boats. Getting the truck wet is just too expensive in the long run.
I'd rather deal with the extra length than fight with trying to launch and load with the bow right up behind the truck.
A buddy has a 14' tinny on a trailer so short that the bow is nearly right over the coupler. He had to back in till the back wheels are wet up to the rims just to get the boat to float.
I replaced the 7 foot tongue on my Load Rite with a 9 foot tongue....I was able to get a factory Load Rite one from trailerpartsdepot.com and the great thing was the factory one had all the holes already drilled in the right places...and it is thicker gauge steel than the old one...Replacing a tongue is a little tricky as you have to get the bolt that goes through both side rails and the tongue out but once you figure that out it's pretty easy. I also made up another cross brace to make sure it didn't flex too much as I noticed the bigger Load Rites now come with an additional brace. Tought to drill through that steel though...took a while! I added longer roller bars (thicker steel also) and that made a big difference. Now I can launch easily without getting my rear wheels in the salt water.