Needs a set of very long lines to run from Leader, thru rings on wheeler bridle, then thru terret rings that are split horizontally to keep reins apart. Leader can wear a single horse harness but needs trace carriers. Not sure of “the look” in draft hitches, but traces “probably” go back to a set of singltrees hung off the wheeler’s collar. This was so both horses could actually pull the load while delivering in narrow alleys and city streets in the old days. Drafts may have some unique way of connecting the leader I don’t know about.
The carriage folks often shortcut with very long leader traces and two unique pieces of metal called “Tandem keys” that fit on wheeler trace buckles instead of using singletrees. Usually no breeching on leader because she can’t hold anything without shafts or a pole! Less to polish!
He needs a whip with lash that reaches the leader, should she need a touchup for forward.
Then the fun, not all horses will work as leaders!! A leader MUST be forward, brave and BOLD out there alone. No partner for confidence. They have to respond well to voice commands and Driver has to have nimble fingers!! What works in feel, pressure with a Pair or Four needs to be half or less on the Tandem leader. Even then leader may whip around, stop by the carriage for a pat, because she got too much (a twitch!) rein pull in a turn!!
Suggestion with new Tandem is having ground person lead the leader for a while, get her used to being alone, out front. Getting her forward may take a while to understand. STRONG suggestion to NEVER take the Tandem out alone!! Things can go bad in a heartbeat, second person can save you, untangle horses, fix trace the leg went over, pull the leader back straight. Driver alone CANNOT do any of that. Tandems are just faster in every area, especially when it goes wrong!! And it will, even in the arena.
You only create a good Tandem by diving them a LOT, put the miles on them. If his chosen leader is not improving after some time, he may want to exchange the horses, try the wheeler as leader instead. We have done two Tandems and a three with the Pair and a leader. Each took a good while to get improved. More than a couple months of regular driving sessions. Leaders were used to being in Pairs, not out alone in front. The three horses were actually the worst, he was not as brave as we wanted, though a terrific leader in the Four. The Tandems were for CDE competition, so needed to be very brave leaders, FORWARD even when we could not see ahead on curves. Different horses in both Tandems, so started from scratch each time. They were pretty good for Fall competition with Feb/March starting Tandem driving. Leaders were BROKE, obedient, excellent driving horses. Pretty unflappable everywhere, to add this knowledge on. We STILL had issues to work thru to get them correct, understanding what we wanted. Then there were the harness modifications to make things safer, improve their drivability. But they were light horses, we were going to ask MUCH from them. Perhaps the potential draft Tandem won’t be working at that speed or skill level, to be so highly polished, yet still very enjoyable to drive.
Tandems do keep your blood racing, which scours out all your veins and arteries!!
Driver WILL want to practice using that long lash whip, throwing lash out, bringing it back without hitting wheeler area, not tangling in harness or wheels. Best practice is sitting on the tall carriage/wagon/cart seat, hitting paper targets on bales where horses would be. Close the aisle doors so the neighbors don’t see you acting “peculiar”! Ha ha Driver NEEDS to be able to hit what he aims at.