Peaches bear on last year's wood, every year you will need to prune it to head that wood back and to remove old wood to make room for new. Pruning that one for size won't be any additional work. But it may be easier to do all the pruning on the peach if it's not 15'. The pear will bear on long lived spurs so it will require very little pruning (if it's well behaved) once it's trained and probably reach larger than expected if you don't do size pruning. So you can only consider "to prune or not to prune" with the pear, and even then you're going to have damage control and thinning of some branches required. I've seen companies that were right on the money with their estimates and I've seen companies that greatly underestimate their sizes. I have never seen a company predict a huge size and hand out dwarf sizes. My rule of thumb is that if it's going to be other than claimed it will err to the large side. I've seen trees bought as dwarfs that dwarf my accurately sized semi-dwarf apple that's pushing 20 years with very little pruning later in life. I'd go dwarf for both. If you flipped the planting spaces around I may change to semi-dwarf for the pear just to get more fruit. But I wouldn't want to be climbing 15' to head back branches or be thinning out old 15' branches.

Prune the branch cluster (mainly the sides in your case) to a 3x3' "ball" shape in Fall after the blooms are spent. For reference, the new left edge would be approximately where the edge of the right-front corner of bumper on your SUV is, if you were looking at it from the same angle as your picture. Also, if you are going to let the tree grow to a fuller size, you might want to back it further away from the driveway edge as these can begin to spill into the path of it. Either way, if you don't prune narrower at the top, they will tend to continue growing wider first and not taller. Alternatively, if you keep the branch cluster pruned to the same diameter each year, the main trunk should continue to get thicker and a bit taller. So I would start with a 3x3' ball and after the trunk becomes thicker keep pruned to a 6x6' ball, provided it is not hanging into the driveway.

I've done some more research since posting. if you're just starting out you can prune them the same as muscadines on a single wire with two cordons and spurs. there are a number of people I've spoken to that have had good success that way. it is probably not the best for a commercial venture but for the home garden it will apparently provide gallons of kiwi. Do you have a male planted nearby? I planted a pair (male and female) in the same hole the other day on a new trellis i started, we have some pollination issues that limit fruit set.

every leaf is a food making machine.. to grow the roots... to get the tree ESTABLISHED... a tree is thought to be twice as large underground.. in a pancake shape .. than what you see above ... ergo ... you should think about how much roots your trees need to grow ... based on the relatively small ball of roots planted ... until they start growing to expectation ... imo.. it makes no sense to cut off the top.. to try to make the tree look more mature .. including thickening of the trunk ... it seems it would be counter productive ... thats a lot of bare soil.. the trees would benefit from a mulch ring.. to preserve water in the root zone ... in hindsight.. i would not have bought those trees ... it is suggested that smaller transplants go thru less stress .. grow the requisite roots.. and usually outgrow larger transplants in the long run ... and cost a lot less ...but thats water under the bridge.. and for next purchase ... regardless of how long you want to stake a tree... you should adjust the tie downs at least twice a year .. to insure that the tree is not being damaged ... also.. a smaller plant would have been easier to stake ... usually you do allow some movement.. because as dylon said.. they are suppose to blow in the wind .. but i am not sure with these specific trees.. that would be advisable .. to any great extent ... ken https://www.youtube.com/watch?v=G58XWF6B3AA