Is there a way to make the driver direct drive on high?
Nope.
Bummer. I guess add more 7135's.
You can add one more chip to get 3.15 amps or 2 more to get 3.5 amps.
If you can do that good a job on those, I’ll be sending you all my boards when they need to be soldered. When I try it, there’s usually nothing left on the board except a pile of solder and wet spots from tears…
It takes a lot of practice and a very tiny soldering iron tip. A trick I use is to blob solder on the chips on the board first then use alligator clamps to hold the added chip on and very lightly heat the premade blob and they usually stick. I will admit I have wrecked quite a few but I just harvest the chips off it when that happens. Oh yeah and use a magnifying glass my old eyes can't see those tiny connections.
A lot of practice helps to.
wow i wish i had ll those 
" When I try it, there's usually nothing left on the board except a pile of solder and wet spots from tears... "
BWAAAHAHAHAHAHAHAHAHAHAHA !
I just love that comment , Old-lumens
I also want to add some 7135s to stack them. Any advice besides a steady hand and a tiny soldering iron tip? I have a Weller iron but no tiny soldering tips. Any recommendations for an iron compatible with a TINY tip for this type of thing?